question_answer

What is the change in momentum of a car weighing 1500 kg when its speed increases from 36 km/h to 72 km/h uniformly?

Answer:

mass = 1500 kg, u = 36 km/h = 10 m/s \[v=72km/h=20m/s\] Now, initial momentum\[=m\,u\] \[=1500\times 10kg\,\,m/s=15000kg\,\,m/s\] final momentum\[u=-20m/s\] \[=1500\times 20kg\,\,m/s=30000kg\,\,m/s\] \[\therefore \] change in momentum\[=mv-mu\] \[=(30000-15000)kg\,\,m/s=15000\,\,kg\,\,m/s.\]