Question

3. 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

Answer: (c) 2000 N

Explanation:

Given Data :

▪ Initial velocity = zero ( body is at rest)

▪ Distance travelled = 100m

▪ Final kinetic energy = 200000J

To Find :

▪ Resultant force acting on the car.

Therefore:

W = F × d = ΔK ----------------- eq 1.

where,

W = work done

F = applied force

d = distance

ΔK = change in kinetic energy

Calculation :

→ F × d = Kf - Ki ----------------- eq 2.

Where:

Kf = Final kinetic energy = 200000

Ki = initial kinetic energy = 0

Substituting our values into the formula from equation (2)

→ F × 100 = 200000 - 0

→ F = 200000/100

→ F = 2000N