Question

Calculate the work required to be done to stop a car of 1500 kg moving at a speed of 54 kilometre

Answer 1

Mass = 1500 kg

velocity = 54km/hr

= 54 × 5/18 cut 54 by 3 and 18 also.

= 15m/s

t = 5 sec

a = v/t = 15/5 = 3m/sec²

R = ma

= 1500 × 3

= 4500 N

Answer 2

Answer:

Solution: Kinetic energy, E k= 1/2 mv^2

Where,

Mass of car, m= 1500 kg

Velocity of car, v= 60 km/hr= (60 — 5 )/(18 ms^(-1) )

ˆ´ E k= 1/2 — 1500 — €–(60 — 5/18)€—^2 = 20.8 —€–10€—^4 J

Hence, 20.8 — 104 J of work is required to stop the car.