Question

how much energy is gained by a box of mass 20kg when man
(a)carrying wait for 5 minutes for a bus?
(b) run carrying the box with a speed of 3m/s to catch the bus?
(c)raise the box by 0.5 in order to place it inside the bus?

Answer 1

a)P.E=m*g*h=20*9.8*0=0

b)K.E=1/2*m*v^2=1/2*20*3^2=90kgm^2/s^2

c)a)P.E=m*g*h=20*9.8*0.5=9.8kgm^2/s^2