Question

A 27 kg child slides down a playground slide at a constant speed. The slide has a height of 4.0 m and is 7.0 m long. Part A Using the law of conservation of energy, find the magnitude of the kinetic friction force acting on the child.

Answer 1

Step-by-step explanation:

The forces acting along the playground are:

Kinetic friction force Fk and

Wsintheta (weight along the plane)

Since sintheta = opp/hyp

Sintheta = 4/7

Taking the sum of forces along the playground

\sumFx = max

Wsintheta - Fk = max

Since the speed is constant, ax = 0, the equation becomes

Wsin theta - Fk = 0

Fk = Wsintheta

From the question

W = mg

W = 27×9.81

W = 264.87N

Fk = 264.87 × 4/7

Fk = 1059.48/7

Fk = 151.35N

Hence the magnitude of the kinetic friction force acting on the child is 151.35N