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

Initial velocity of the truck, u = 0 m/s 

Time taken, t = 20 s 

Distance covered by the stone, s = 400 m 

According to the second equation of motion: 

s = ut + 1/ 2 at ² 

We have 

400 = 0 × 20 + 1 /2 × × (20) ² 

⇒ 400 = 200 

⇒ = 2 m/s2 

Now, Force = mass × acceleration 

⇒ F = 7000 × 2 = 14000 N