Question

A 20-kg child is tossed up into the air by her parent. The child is 2 meters off the ground traveling 5 m/s.

Circle one: KE / GPE / both

Show your work for finding the values of each type of energy the object has

Answer 1

Data:
m (mass) = 20 Kg
h (height) = 2 m
s (speed) = 5 m/s
$K_{E} = ?$ kinetic energy (Joule)
GPE (Gravitational potential energy ) = ? (joule)
Both = KE + GPE = ?
Adopting: g (gravity) = 10 m/s²

Solving: (Kinetic Energy)
$K_{E} = \frac{m*s^2}{2}$
$K_{E} = \frac{20*5^2}{2}$
$K_{E} = \frac{20*25}{2}$
$K_{E} = \frac{500}{2}$
$\boxed{K_{E} = 250\:J}\end{array}}\qquad\quad\checkmark$

Solving: GPE
$GPE = m*g*h$
$GPE = 20*10*2$
$\boxed{GPE = 400\:J}\end{array}}\qquad\quad\checkmark$

Solving: Both (KE + GPE)
$Both = K_{E} + GPE$
$Both = 250+400$
$\boxed{Both = 650\:J}\end{array}}\qquad\quad\checkmark$