Question

A loaded truck moving with a velocity of 10kmh^-1 at a distance 10m away from a rail line applies brake suddenly to see a train running and stops in 5 seconds. Mass of empty truck and load are 1500kg and 400kg respectively.

1. How much distance did the truck travel after applying brake? Find out.
2. If the truck is not loaded, driver can stop the truck easily. Analyze with logic

Answer 1

1.

breaking distance:

$d=v_0t-at^2/2$

$a=v_0/t$

$d=v_0t/2=10\cdot5/(2\cdot3.6)=6.94\ m$

2.

Since the mass is less, then kinetic energy of truck is more. So, it is required more energy to stop the truck.