Question

A child and sled with a combined mass of 50.0 kg slide down a frictionless slope. if the sled starts from rest and has a speed of 4.00 m/s at the bottom, what is the height of the hill? m

Answer 1

Answer:

The height of the hill is 0.81 m

Explanation:

It is given that,

Mass of child and sled, m = 50 kg

The sled starts from rest and has a speed of v = 4 m/s

We have to find the height of the hill. It can be calculated using conservation of energy. The potential energy at the bottom of hill is 0 and at maximum height the kinetic energy is 0.

So, $\dfrac{1}{2}mv^2=mgh$

$h=\dfrac{v^2}{2g}$

$h=\dfrac{(4\ m/s)^2}{2\times 9.8\ m/s^2}$

h = 0.81 m

So, the height of the hill is 0.81 m. Hence, this is the required solution.                                        

Answer 2

             Using conservation of energy

Potential Energy (Before) = Kinetic Energy (After)

mgh = 0.5mv^2

divide both sides by m

gh = 0.5v^2

h = (0.5V^2)/g

h = (0.5*2.2^2)/9.81

h = 0.25m