Question

A truck starts from rest and rolls down a hill with a constant acceleration. It travels a distance of 400 m in 20 s. Find its acceleration. Find the force acting on it if its mass is 7 metric tonnes (Hint: 1 metric tonne = 1000 kg).

Answer 1

Distance covered by the truck (s) = 400 m

Time (t) = 20 s

Initial velocity (u) = 0

Mass of the truck: m = 7 tons = 7000 kg (1 metric ton = 1000 kg)

According to the second equation of motion

S = ut + 12at²

400 = 0 × 20 + 12 × a × (20)²

a = 2m/s²

Hence, acceleration of the truck = 2m/s²

Since force (F) = mass × acceleration (a),

F = 7000 × 2

F = 14000N

Hence, force applied on the truck = 14000 N