Question

A 15 kg child slides down a 5 m tall (vertical) slide that is inclined to the horizontal 34°. Her velocity is 5 m/s at the bottom of the sled. How much mechanical energy was lost to friction?

Answer 1

547.5 J

Step-by-step explanation

Given:

• The child's mass, m = 15 kg

,

• The height of the slide, h = 5 m

,

• The velocity of the child at the bottom of the slide, v = 5 m/s

Find:

• The loss of mechanical energy due to friction

The loss of mechanical energy due to friction is the difference between the child's gravitational potential energy at the top of the slide, and the child's kinetic energy at the bottom of the slide,

`PE-KE=mgh-(1)/(2)mv^2`

Replace the known values and solve,

`PE-KE=15kg\cdot9.8m/s^2\cdot5m-(1)/(2)\cdot15kg\cdot5^2m^2/s^2=735J-187.5J=547.5J`

Hence, 547.5 Joules of energy were lost due to friction.