Answer:
K.E = 248 J
Explanation:
Since the child is travelling at a given velocity. The kinetic energy of the child down the hill can be given by the following formula:
[tex]K.E = \frac{1}{2}mv^2\\[/tex]
where,
m = mass of the child = 31 kg
v = velocity of the child = 4 m/s
Therefore,
[tex]K.E = \frac{1}{2}(31\ kg)(4\ m/s)^2\\[/tex]
K.E = 248 J