Question

A child throws a ball vertically upwards with a velocity 20 m s–1.
(a) At what point is the kinetic energy maximum?
(b) At what point is the potenital energy maximum?

Answer 1

Answer:

（b）The point where velocity becomes zero

Answer 2

Answer:

kinetic energy is maximum at time of throw or when ball reaches ground.

potential energy. is maximum at max height

Explanation:

A child throws a ball vertically upwards with a velocity 20 m s–1.

kinetic energy = (1/2)mv^2

=(1/2)m(20)^2

= 200m

potential energy= mgh =0

kinetic energy is maximum at time of throw

at max height when velocity become zero

height achieved= h

0^2 - v^2 = 2(-g)h

h = 200/g

potential energy at max height=mgh

= mg(200/g)

=200m

kinetic energy at max height=(1/2)mv^2

= 0

potential energy. is maximum at max height