How much work is to be done to increase the velocity of a car from 18 kmh-1 to 72 kmh-1, if the mass of the car is 2000 kg?
Answers
Answered by
3
Answer:
Work Done = The Change in Kinetic Energy
= 1/2mv2 - 1/2 mu2
The Mass of car = 2000 kg
Initial Velocity = 18 km/h
= 18 * 5 / 18
= 5
= 5 m/s
Final Velocity = 72 km/hr
= 72 * 5/18
= 5 * 4
= 20 m/s
Work Done = 1/2 mv2 - 1/2 mu2
= 1/2 m(v2 - u2)
= 1/2 * 2000 ( 20 * 20 - 5 * 5)
= 1000 ( 400 - 25)
= 1000 * 375
= 375000 J
Answered by
1
Answer:
u = 18 km/h = 5 m/s
v = 72 km/h = 20 m/s
m = 2000 kg
Initial kinetic energy = 1/2*2000*(5)^2 = 25000 J
Final kinetic energy = 1/2*2000*(20)^2 = 400000 J
Work done = Change in KE = 400000 - 25000 = 375000 J
Similar questions