Question

how much energy is gained by a box of mass 20kg when a man 1.) carrying the box waits for 5 minutes for a bus 2.) runs carrying the box with speed of 3m per second to catch the bus?3.) raises the box by 0.5 m in order to place it inside the bus ?(g= 10 m per second square )

Answer 1

. zero because it is at rest

2.1/2 ×20 ×3×3

=90j

3 mgh =20×10×0.5

=100,j

I hope it will help you