Question

A child, starting from rest, slides down a 2.5 m high ramp. At the bottom of the ramp, the child has a speed of 4.0 m/s. If 580 J is lost to heat, determine the mass of the child.

Answer 1

35 kg

Step-by-step explanation:

Initial energy = final energy

Potential energy = kinetic energy + heat

PE = KE + Q

mgh = ½ mv² + Q

m (gh − ½ v²) = Q

m = Q / (gh − ½ v²)

Plug in values:

m = 580 J / [ (9.8 m/s²) (2.5 m) − ½ (4.0 m/s)² ]

m = 35 kg