Question

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

Answer 1

Given :-

• Initial velocity (u) = 0
• Distance (s) = 400m
• Time (t) = 20s
• Mass (m) = 7 tonnes

To find :-

• Acceleration
• Force

Solution :-

According to the second equation of motion

→ s = ut + ½ at²

→ 400 = 0 × 20 + ½ × a × (20)²

→ 400 = ½ × a × 400

→ 400 = 200a

→ a = 400/200 = 2m/s²

Hence,

• Acceleration of truck = 2m/s²

As we know that

• 1 tonne = 1000kg
• 7 tonne = 7*1000 = 7000kg

→ Force = mass × acceleration

→ F = ma

→ F = 7000 × 2

→ F = 14000N

Hence,

• Force acting is 14000N