question_answer

Draw the velocity-time graph from the data given below.

Time (in s)	2	4	6	8	10	12	14
Velocity (in m/s)	5	10	15	20	20	10	0

(i) What type of motion is represented by the object during 0-6 s? (ii) Calculate the acceleration in first 6 s. (iii) Calculate the distance travelled between 6-8 s. (iv) Calculate the retardation during 12-14 s. OR On a 100 km track, the train travels the first 30 km at a uniform speed of 30 km/h. How fast must the train travel the next 70 km so as to make average speed 40 km/h for the whole trip?  

Answer:

                                                                                                                                                         (1) (i) From (0-2)s motion is not defined. From (2-6)s motion is uniform.                                                                       (1) (ii) Acceleration from 2-6 s                                                                                   (1) (iii) Distance travelled between 6-8s is given by the area of ABCD as shown in figure. Area of area of rec,                                                                     (1)                                                 (1) (iv)Retardation between (12-14) s.                                                          (1) OR Average speed   Time taken by the train in going from O to A                                                        (1) Time taken by the train in going from A to B But average speed,                                                  (2) or                            or                   (2)