9th Class Science Force and laws of motion Question Bank

done Force and Laws of Motion Total Questions - 60

• question_answer1)
  An unbalanced force acts on a body. What happens to the body?
  A)
   The body remains at rest. done clear
  B)
   The body must move with uniform velocity. done clear
  C)
   The body is accelerated.   done clear
  D)
   The body moves along a circle. done clear
  View Solution play_arrow

• question_answer2)
  If no force acts on a body, then what will happen to it?
  A)
   It does not change its shape. done clear
  B)
   It continues to move but with less speed. done clear
  C)
   It changes its direction. done clear
  D)
   It can either remain at rest or continue to move in a straight line.   done clear
  View Solution play_arrow

• question_answer3)
  How much mass (approximately) of a body one can hold/when a force of \[1\,\,N\] is applied on it?
  A)
  \[100\,\,mg\]       done clear
  B)
         \[100\,\,g\]   done clear
  C)
  \[1\,\,kg\]                       done clear
  D)
         \[10\,\,kg\] done clear
  View Solution play_arrow

• question_answer4)
  When a bus starts suddenly, the passengers are pushed backwards. Which of the following laws is illustrated in this example?
  A)
   Newton's first law   done clear
  B)
   Newton's second law done clear
  C)
   Newton's third law done clear
  D)
   None of Newton's laws done clear
  View Solution play_arrow

• question_answer5)
  A force of a given magnitude acts on a body. On what factors does the acceleration of the body depend?
  A)
   Density of the body done clear
  B)
   Volume of the body done clear
  C)
   Mass of the body   done clear
  D)
   Shape of the body done clear
  View Solution play_arrow

• question_answer6)
  What does the principle of conservation of linear momentum state?
  A)
   The linear momentum of a system cannot be changed. done clear
  B)
   The linear momentum of a system cannot remain constant. done clear
  C)
   The linear momentum of a system can be changed only if internal forces act. done clear
  D)
   The linear momentum of a system can be changed only if external forces acts on it.   done clear
  View Solution play_arrow

• question_answer7)
  On which of the following do action-reaction forces act upon?
  A)
   Same body done clear
  B)
   Different bodies   done clear
  C)
   Along different lines done clear
  D)
   In the same direction done clear
  View Solution play_arrow

• question_answer8)
  Consider a porter standing on a platform with a suitcase which presses his head with a force of\[200\,\,N\]. If this force is taken to be the action, from where is the reaction force exerted and to where is it directed?
  A)
   The head, on the suitcase   done clear
  B)
   The earth, on the suitcase done clear
  C)
   The earth, on the porter done clear
  D)
   The suitcase, on the earth done clear
  View Solution play_arrow

• question_answer9)
  A force produces an acceleration of \[5.0\,\,cm\,\,{{s}^{-2}}\] when it acts on a body of mass\[20\,\,g\]. Find the force acting on the body.
  A)
  \[1\times {{10}^{-3}}N\]             done clear
  B)
         \[2\times {{10}^{-3}}N\] done clear
  C)
  \[4\times {{10}^{-3}}N\]           done clear
  D)
         \[5\times {{10}^{-3}}N\] done clear
  View Solution play_arrow

• question_answer10)
  A force acts on a body of mass\[200\,\,g\]. The velocity of the body changes from \[15\,\,m\,\,{{s}^{-1}}\] to \[25\,\,m\,\,{{s}^{-1}}\] in\[2.5\,\,s\]. What is magnitude of the force, assuming the force to be constant?
  A)
  \[0.4\,\,N\]         done clear
  B)
         \[0.5\,\,N\] done clear
  C)
  \[0.6\,\,N\]         done clear
  D)
         \[0.8\,\,N\]   done clear
  View Solution play_arrow

• question_answer11)
  A force of 0.6 N acting on a particle increases its velocity from 5.0 m s~1 to 6.0 m s-1 in 2 s. What is the mass of the particle?
  A)
  \[1.2\,\,kg\]           done clear
  B)
         \[2.2\,\,kg\] done clear
  C)
  \[4.2\,\,kg\]         done clear
  D)
         \[6.2\,\,kg\] done clear
  View Solution play_arrow

• question_answer12)
  A force acting on a particle of mass \[200\] displaces it through \[400\,\,cm\] in \[2\] seconds. Find the magnitude of the force if the initial velocity of the particle is zero.
  A)
  \[0.1\,\,N\]         done clear
  B)
         \[0.3\,\,N\] done clear
  C)
  \[0.4\,\,N\]           done clear
  D)
         \[0.5\,\,N\] done clear
  View Solution play_arrow

• question_answer13)
  A body of mass \[300\,\,g\] at rest breaks into two parts due to internal forces. One part of mass \[200\,\,g\] is found to move at a velocity of \[12\,\,m\,\,{{s}^{-1}}\] towards east. Find the velocity of the other part.
  A)
   \[-24\,\,m\,\,{{s}^{-1}}\]towards west   done clear
  B)
   \[14\,\,m\,\,{{s}^{-1}}\]towards east done clear
  C)
   \[24\,\,m\,\,{{s}^{-1}}\]towards north done clear
  D)
   \[54\,\,m\,\,{{s}^{-1}}\]towards south done clear
  View Solution play_arrow

• question_answer14)
  A mass of \[2\,\,kg\] at rest travels for \[4\] seconds with an acceleration of\[1.5\,\,m\,\,{{s}^{-2}}\]. Find the gain of the momentum of the body.
  A)
  \[5\,\,kg\,\,m\,\,{{s}^{-1}}\]       done clear
  B)
         \[10\,\,kg\,\,m\,\,{{s}^{-1}}\] done clear
  C)
  \[12\,\,kg\,\,m\,\,{{s}^{-1}}\]       done clear
  D)
         \[14\,\,kg\,\,m\,\,{{s}^{-1}}\] done clear
  View Solution play_arrow

• question_answer15)
  Due to an impulse, the change in the momentum of a body is\[1.8\,\,kg\,\,m\,\,{{s}^{-1}}\]. If the duration of the impulse is\[0.2\,\,s\], then what is the force produced in it?
  A)
  \[9\,\,N\]                          done clear
  B)
         \[8\,\,N\] done clear
  C)
  \[7\,\,N\]                                    done clear
  D)
  \[6\,\,N\] done clear
  View Solution play_arrow

• question_answer16)
  Which of the following are vector quantities?
  A)
   Force                done clear
  B)
          Velocity done clear
  C)
   Momentum       done clear
  D)
          All of the above   done clear
  View Solution play_arrow

• question_answer17)
  Two bodies collide at the same temperature. Which of the following is conserved?

  (i) Velocity

  (ii) Momentum

  (iii) Kinetic energy

  A)
   Only (i) and (ii) done clear
  B)
   Only (ii) and (iii)   done clear
  C)
   Only (i) and (iii) done clear
  D)
   (i), (ii) and (iii) done clear
  View Solution play_arrow

• question_answer18)
  Vehicles are provided with shock absorbers. Which of the following laws of Newton given below explain this?
  A)
   The first law of motion done clear
  B)
   The second law of motion   done clear
  C)
   The third law of motion done clear
  D)
   All of the above done clear
  View Solution play_arrow

• question_answer19)
  On what principle does a jet engine work?
  A)
   Conservation of linear momentum   done clear
  B)
   Conservation of kinetic energy done clear
  C)
   Conservation of angular momentum done clear
  D)
   Conservation of inertia done clear
  View Solution play_arrow

• question_answer20)
  A ball of mass \[100\,\,g\] is moving with a velocity of\[10\,\,m\,\,{{s}^{-1}}\]. The force of the blow by the bat acts for \[0.01\] seconds. What is the force exerted on the ball by the bat?
  A)
  \[100\,\,N\]         done clear
  B)
         \[200\,\,N\]   done clear
  C)
  \[300\,\,N\]         done clear
  D)
         \[400\,\,N\] done clear
  View Solution play_arrow

• question_answer21)
  A body is at rest on the surface of the earth. Which of the following statements is correct?
  A)
   Only the weight of the body acts on it. done clear
  B)
   Only upward force acts on the body. done clear
  C)
   Frictional force acts on the body. done clear
  D)
   Net upward force is equal to the net downward force.   done clear
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• question_answer22)
  A book is lying on a table. What is the angle between the book on the table and the weight of the book?
  A)
  \[{{0}^{o}}\]                 done clear
  B)
         \[{{45}^{o}}\] done clear
  C)
  \[{{90}^{o}}\]             done clear
  D)
         \[{{180}^{o}}\] done clear
  View Solution play_arrow

• question_answer23)
  \[E,\,\,G\] and \[N\] represent the magnitudes of electromagnetic, gravitational and nuclear forces respectively between two electrons placed apart at a given distance. How are the magnitudes of \[E,\,\,G\] and \[N\] related to each other?
  A)
  \[E>G>N\]        done clear
  B)
         \[E>N>G\] done clear
  C)
  \[G>N>E\]        done clear
  D)
         \[N>E>G\]   done clear
  View Solution play_arrow

• question_answer24)
  A \[60\,\,kg\] man pushes a \[40\,\,kg\] man with a force of 60 N. With what force does the\[~40\,\,kg\] man push the other man?
  A)
  \[40\,\,N\]          done clear
  B)
         \[0\,\,N\] done clear
  C)
  \[60\,\,N\]            done clear
  D)
         \[20\,\,N\] done clear
  View Solution play_arrow

• question_answer25)
  When a horse pulls a cart, what is the force that helps the horse move forward?
  A)
   The force exerted by the cart on the horse done clear
  B)
   The force exerted by the ground on the horse   done clear
  C)
   The force exerted by the ground on the cart done clear
  D)
   The force exerted by the horse on the cart done clear
  View Solution play_arrow

• question_answer26)
  On what factors does the inertia of motion depend?
  A)
   Mass                  done clear
  B)
          Velocity done clear
  C)
   Acceleration   done clear
  D)
          Displacement done clear
  View Solution play_arrow

• question_answer27)
  Which of the following physical quantities has the same units as that of impulse?
  A)
   Momentum         done clear
  B)
          Force done clear
  C)
   Torque             done clear
  D)
          Couple done clear
  View Solution play_arrow

• question_answer28)
  A cricket ball weighing \[100\,\,g\] and moving with a speed of \[20\,\,m\,\,{{s}^{-1}}\] strikes a bat and remains in contact with it for\[0.1\,\,s\]. What is the force exerted by the ball on the bat?
  A)
  \[100\,\,N\]         done clear
  B)
         \[-10\,\,N\] done clear
  C)
  \[-40\,\,N\]           done clear
  D)
         \[1N\] done clear
  View Solution play_arrow

• question_answer29)
  A \[10\,\,N\] force applied on a body produces in it an acceleration of\[2\,\,m\,\,{{s}^{-2}}\]. What is the mass of the body?
  A)
  \[20\,\,kg\]          done clear
  B)
         \[0.2\,\,kg\] done clear
  C)
  \[5\,\,kg\]                         done clear
  D)
         \[200\,\,g\] done clear
  View Solution play_arrow

• question_answer30)
  If soldiers had the options to use guns of different weights but the bullets used are of a fixed weight, what would they prefer and why?
  A)
   Light guns, because handling them is easy done clear
  B)
   Heavy guns, because they can be held firmly done clear
  C)
   Heavy guns because they have less recoil   done clear
  D)
   Light guns, because they can be carried easily done clear
  View Solution play_arrow

• question_answer31)
  A force acts for \[10s\] on a body of mass \[10\,\,kg\] after which the force ceases and the body travels \[50\,\,m\] in the next\[5\,\,s\]. Find the magnitude of the force.
  A)
  \[5\,\,N\]                        done clear
  B)
         \[10\,\,N\]   done clear
  C)
  \[15\,\,N\]          done clear
  D)
         \[50\,\,N\] done clear
  View Solution play_arrow

• question_answer32)
  A cricket ball of mass \[500\,\,g\] is moving with a speed of\[36\,\,km\,\,{{h}^{-1}}\]. It is reflected with the same speed. What is the impulse applied on it?
  A)
  \[20\,\,kg\,\,m\,\,{{s}^{-1}}\]     done clear
  B)
         \[5\,\,kg\,\,m\,\,{{s}^{-1}}\] done clear
  C)
  \[25\,\,kg\,\,m\,\,{{s}^{-1}}\]     done clear
  D)
         \[10\,\,kg\,\,m\,\,{{s}^{-1}}\]   done clear
  View Solution play_arrow

• question_answer33)
  The velocity-time graph of a ball moving on the surface of a floor is given below. Calculate the force acting on the ball, if the mass of the ball is\[200\,\,g\].
  A)
  \[1\,\,N\]                          done clear
  B)
         \[2\,\,N\] done clear
  C)
  \[5\,\,N\]                        done clear
  D)
         \[8\,\,N\] done clear
  View Solution play_arrow

• question_answer34)
  China wares are wrapped in straw or paper before packing. What is the basis of this application?
  A)
   Impulse              done clear
  B)
          Momentum done clear
  C)
   Acceleration      done clear
  D)
          Force done clear
  View Solution play_arrow

• question_answer35)
  A motor car running at the rate of \[7\,\,m\,\,{{s}^{-1}}\] is stopped by applying the brakes after it travels\[10\,\,m\]. Find the total resistance to the motion when the brakes are on.
  A)
   It is one-fourth of the weight of the car.   done clear
  B)
   It is two-thirds of the weight of the car. done clear
  C)
   It is one-eighth of the weight of the car. done clear
  D)
   It is four-fifths of the weight of the car. done clear
  View Solution play_arrow

• question_answer36)
  A bullet of mass \[60\,\,g\] moving with a velocity of \[500\,\,m\,\,{{s}^{-1}}\] is brought to rest in 0.01 s. Find the impulse and the average force of the blow.
  A)
  \[-3\,\,N\,\,s,\,\,3\,\,k\,\,N\] done clear
  B)
         \[-30\,\,N\,\,s,\,\,-3\,\,k\,\,N\]   done clear
  C)
  \[-50\,\,N\,\,s,\,\,-5\,\,k\,\,N\] done clear
  D)
  \[-60\,\,N\,\,s,\,\,-6\,\,k\,\,N\] done clear
  View Solution play_arrow

• question_answer37)
  If the same force is applied on two bodies of different masses for the same time, what happens to the momentum of the two bodies?
  A)
   The momenta increases done clear
  B)
   The momenta decreases done clear
  C)
   The momenta remains the same   done clear
  D)
   The momenta may increase or decrease done clear
  View Solution play_arrow

• question_answer38)
  Match the entries in Column I with those in Column II.

  	Column-I		Column-II
  [a]	Force	1.	\[N\,\,{{m}^{-2}}\]
  [b]	Weight	2.	\[Kg\]
  [c]	Pressure	3.	\[N\]
  [d]	Impulse	4.	\[N\,\,s\]
  [e]	Mass	5.	\[Kg\,\,wt\]

  A)
   a - 3, b - 2, c - 4, d - 1, e - 5 done clear
  B)
   a - 5, b - 4, c - 3, d - 1, e - 2 done clear
  C)
   a - 3, b - 5, c - 1, d - 4, e - 2   done clear
  D)
   a - 4, b - 2, c - 1, d - 3, e - 5 done clear
  View Solution play_arrow

• question_answer39)
  A cricket ball of mass \[120\,\,g\] is moving with a velocity of\[12\,\,m\,\,{{s}^{-1}}\]. It turns back and moves with a velocity of \[20\,\,m\,\,{{s}^{-1}}\] when hit by a bat. Find the impulse if the force acts on the ball for\[0.02\,\,s\].
  A)
  \[4N\,\,s\]           done clear
  B)
         \[8N\,\,s\] done clear
  C)
  \[32N\,\,s\]         done clear
  D)
         \[192N\,\,s\]   done clear
  View Solution play_arrow

• question_answer40)
  In a game of tug of wars, a condition of equilibrium exists. Both the teams pull the rope with a force of\[{{10}^{4}}N\]. Find the tension in the rope.
  A)
  \[0N\]                done clear
  B)
         \[{{10}^{4}}N\]   done clear
  C)
  \[{{10}^{5}}N\]           done clear
  D)
         \[2\times {{10}^{4}}N\] done clear
  View Solution play_arrow

• question_answer41)
  A truck and a car are moving with equal velocity. On applying brakes, if both decelerate at the same rate, what happens?
  A)
   The truck will cover less distance before stopping. done clear
  B)
   The car will cover less distance before stopping.   done clear
  C)
   Both will cover equal distance. done clear
  D)
   None of the above done clear
  View Solution play_arrow

• question_answer42)
  The accelerated motion of a body changes due to change in
  A)
   speed done clear
  B)
   direction of motion. done clear
  C)
   constant velocity. done clear
  D)
   Both [a] and [b]   done clear
  View Solution play_arrow

• question_answer43)
  A man weighing \[60\,\,kg\] is walking with a uniform velocity of\[4\,\,m\,\,{{s}^{-1}}\]. Calculate the momentum of a man.
  A)
  \[120\,\,m\,\,{{s}^{-1}}\]          done clear
  B)
  \[240\,\,m\,\,{{s}^{-1}}\]   done clear
  C)
  \[360\,\,m\,\,{{s}^{-1}}\]          done clear
  D)
         \[480\,\,m\,\,{{s}^{-1}}\] done clear
  View Solution play_arrow

• question_answer44)
  Two bodies have masses in the ratio of\[3:4\]. When the same force is applied on both the bodies, the first body produces an acceleration of\[6\,\,m\,\,{{s}^{-2}}\]. What is the acceleration produced by the second body?
  A)
  \[-0.25\,\,m\,\,{{s}^{-1}}\]                    done clear
  B)
  \[2.5\,\,m\,\,{{s}^{-1}}\]   done clear
  C)
  \[25\,\,m\,\,{{s}^{-1}}\]            done clear
  D)
         \[250\,\,m\,\,{{s}^{-1}}\] done clear
  View Solution play_arrow

• question_answer45)
  A bullet of mass \[20\,\,g\] is fired from a rifle of \[8\,\,kg\] with an initial velocity of\[100\,\,m\,\,{{s}^{-1}}\]. Find the final velocity of the recoil of the rifle.
  A)
  \[-0.25\,\,m\,\,{{s}^{-1}}\]                      done clear
  B)
  \[2.5\,\,m\,\,{{s}^{-1}}\] done clear
  C)
  \[25\,\,m\,\,{{s}^{-1}}\]            done clear
  D)
         \[250\,\,m\,\,{{s}^{-1}}\] done clear
  View Solution play_arrow

• question_answer46)
  A force of \[100\,\,N\] acts on a body of mass \[2\,\,kg\] for\[10\,\,s\]. Find the change in the velocity of the body.
  A)
  \[100\,\,m\,\,{{s}^{-1}}\]          done clear
  B)
         \[250\,\,m\,\,{{s}^{-1}}\] done clear
  C)
  \[500\,\,m\,\,{{s}^{-1}}\]            done clear
  D)
         \[1000\,\,m\,\,{{s}^{-1}}\] done clear
  View Solution play_arrow

• question_answer47)
  The engine of a car produces an acceleration of\[4\,\,m\,\,{{s}^{-2}}\] in a car, if this car pulls another car of same mass, what is the acceleration produced?
  A)
  \[8\,\,m\,\,{{s}^{-2}}\]  done clear
  B)
         \[2\,\,m\,\,{{s}^{-2}}\]   done clear
  C)
  \[4\,\,m\,\,{{s}^{-2}}\]  done clear
  D)
         \[1/2\,\,m\,\,{{s}^{-2}}\] done clear
  View Solution play_arrow

• question_answer48)
  Which of the following statements is NOT true?
  A)
   When the mass of a body is doubled, the momentum of a body is halved, provided the velocity remains the same.   done clear
  B)
   The pain we feel in the hand on hitting the wall is a consequence of Newton's third law of motion. done clear
  C)
   A table cloth which is pulled from a table without dislodging the dishes is due to inertia of rest. done clear
  D)
   Momentum is a vector quantity. done clear
  View Solution play_arrow

• question_answer49)
  A force acts on a body of mass \[3\,\,kg\] such that its velocity changes from \[4\,\,m\,\,{{s}^{-1}}\] to \[10\,\,m\,\,{{s}^{-1}}\].Calculate the change in the momentum of the body.
  A)
  \[2\,\,kg\,\,m\,\,{{s}^{-1}}\]       done clear
  B)
         \[14\,\,kg\,\,m\,\,{{s}^{-1}}\] done clear
  C)
  \[18\,\,kg\,m\,\,{{s}^{-1}}\]         done clear
  D)
         \[42\,\,kg\,\,m\,\,{{s}^{-1}}\] done clear
  View Solution play_arrow

• question_answer50)
  Which of the following balls is easier to catch even though all of them are moving with the same velocity?
  A)
   Tennis ball   done clear
  B)
   Cricket ball done clear
  C)
   Basketball done clear
  D)
   Both cricket and basket ball done clear
  View Solution play_arrow

• question_answer51)
  A machine gun of mass \[12\,\,kg\] fires \[25\,\,g\] bullets at the rate of \[4\] bullets per second with a velocity of\[500\,\,m\,\,{{s}^{-1}}\]. What force must be applied to the gun to hold it in position?
  A)
  \[20N\]                          done clear
  B)
  \[12.5N\] done clear
  C)
  \[50N\]                done clear
  D)
         \[75N\] done clear
  View Solution play_arrow

• question_answer52)
  Which of the statements given below are applicable for an object to move in a circle?
  A)
   The object must continuously slow down. done clear
  B)
   The object must accelerate.   done clear
  C)
   The object must be acted on by external balanced forces. done clear
  D)
   The object must move with uniform velocity. done clear
  View Solution play_arrow

• question_answer53)
  Which of the following safety features are used in vehicles to reduce the negative effects of inertia?

  (i) Safety seat belts (ii) Automatic air bags (iii) Absorber bumpers

  A)
   Only (i) and (ii) done clear
  B)
   Only (ii) and (iii) done clear
  C)
   Only (i) and (iii) done clear
  D)
   (i), (ii) and (iii)   done clear
  View Solution play_arrow

• question_answer54)
  A gun fires a bullet of mass \[50\,\,g\] with a velocity of\[30\,\,m\,\,{{s}^{-1}}\]. Because of this, the gun is pushed back with a velocity of 1 m s-1.What is the mass of the gun?
  A)
  \[3.5\,\,kg\]         done clear
  B)
         \[30\,\,kg\] done clear
  C)
  \[1.5\,\,kg\]                       done clear
  D)
  \[20\,\,kg\] done clear
  View Solution play_arrow

• question_answer55)
  What is the average force necessary to stop a hammer with a momentum of \[25\,\,N\,\,s\] in\[0.05\,\,s\]?
  A)
  \[500\,\,N\]           done clear
  B)
         \[125\,\,N\] done clear
  C)
  \[50\,\,N\]          done clear
  D)
         \[25\,\,N\] done clear
  View Solution play_arrow

• question_answer56)
  A scooter of mass \[120\,\,kg\] is moving with a uniform velocity of\[108\,\,km\,\,{{h}^{-1}}\]. Calculate the force required to stop the vehicle in\[0.1\,\,s\].
  A)
  \[26000\,\,N\]     done clear
  B)
         \[36000\,\,N\]   done clear
  C)
  \[46000\,\,N\]     done clear
  D)
         \[56000\,\,N\] done clear
  View Solution play_arrow

• question_answer57)
  A lift is moving down with a retardation of\[5\,\,m\,\,{{s}^{-2}}\]. Calculate the percentage change in the weight of the person in the lift\[(g=10\,\,m\,\,{{s}^{-2}})\].
  A)
  \[-25\]                            done clear
  B)
  \[-50\]   done clear
  C)
  \[-75\]                            done clear
  D)
  \[-100\] done clear
  View Solution play_arrow

• question_answer58)
  A force of \[200\,\,N\] acts on a body of mass \[2\,\,kg\] for\[10\,\,s\]. Find the change in the momentum of the body.
  A)
  \[1000\,\,N\,\,s\]  done clear
  B)
         \[250\,\,N\,\,s\] done clear
  C)
  \[500\,\,N\,\,s\]   done clear
  D)
         \[2000\,\,N\,\,s\]   done clear
  View Solution play_arrow

• question_answer59)
  Physical independence of force is a con-sequence of\['X'\]. Identify\['X'\].
  A)
   Newton's third law of motion done clear
  B)
   Newton's second law of motion done clear
  C)
   Newton's first law of motion   done clear
  D)
   All of the above done clear
  View Solution play_arrow

• question_answer60)
  To which of the following laws is the principle of conservation of linear momentum equivalent?
  A)
   Newton's first law of motion done clear
  B)
   Newton's second law of motion done clear
  C)
   Newton's third law of motion   done clear
  D)
   Faraday's Laws done clear
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