Question

A 75-kg student weighs himself by standing on a scale mounted on a skateboard that is rolling down an incline. Assume there is no friction so that the force exerted by the incline on the skateboard is normal to the incline. What is the reading on the scale if = 30º?

Answer 1

The reading on the scale is determined as 636.5 N.

How to calculate the reading on the scale?

The reading on the scale is equal to the normal force exerted on the student by the scale.

The formula for the normal force on an incline is given as;

Fn = mg cosθ

where;

• m is the mass of the student
• g is acceleration due to gravity
• θ is the angle of inclination of the incline

The given parameters include;

mass of the student = 75 kg

acceleration due to gravity = 9.8 m/s²

The reading on the scale is calculated as follows;

Fn = 75 kg x 9.8 m/s² x cos (30)

Fn = 636.5 N

Thus, the reading on the scale is 636.5 N.