Question

A car moves from rest with uniform acceleration along a horizontal road.
After travelling a distance of 100 metres, it has kinetic energy equal to 200000 J. What resultant force is acting on the car?
(a) 100 N (b) 1000 N
(c) 2000 N (d) 20 000 N

Answer 1

Given :

▪ Initial velocity = zero (i.e., rest)

▪ Distance travelled = 100m

▪ Final kinetic energy = 200000J

To Find :

▪ Resultant force acting on the car.

Concept :

☞ This question is completely based on the concept of work-energy theorem.

☞ As per WET, work done by moving body is always equal to the change in kinetic energy.

Mathematically,

✴ W = F × d = ΔK

where,

W denotes work done

F denotes applied force

d denotes distance

ΔK denotes change in kinetic energy

Calculation :

→ F × d = Kf - Ki

→ F × 100 = 200000 - 0

→ F = 200000/100

→ F = 2000N