Question

a body A is moving at the rate of 72km/h .body B is moving in same direction at the rate of 54km/h . when they start, B was 20km ahead of A . after how much distance from position A,A will overtake B​

Answer 1

Answer:

Initial Velocity, u=54km/hr=15m/s

Final velocity , v=72km/hr=20m/s

Mass =1500kg

Initial kinetic energy

2

1

mu

2

⇒

2

1

1500×15×15=168750J

Final kinetic energy

2

1

mv

2

⇒

2

1

1500×20×20=300000J

So, change in kinetic energy = work done=300000−168750=131250J