Question

A seesaw has length 11.0 m and uniform mass 12.8 kg and is resting at an angle of 30

∘
with respect to the ground (see the following figure). The pivot is located at 6.1 m from the end of the seesaw. What magnitude of force (in N ) needs to be applied perpendicular to the seesaw at the raised end so as to allow the seesaw to barely start to rotate?

Answer 1

The magnitude of force needed to be applied perpendicular to the seesaw at the raised end so as to allow the seesaw to barely start to rotate is 62.72 N.

How to calculate the magnitude of the force required?

The magnitude of force needed to be applied perpendicular to the seesaw at the raised end so as to allow the seesaw to barely start to rotate is calculated as follows;

F = mg sin(θ)

where;

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

The magnitude of force needed to be applied perpendicular to the seesaw at the raised end so as to allow the seesaw to barely start to rotate is calculated as;

F = (12.8 kg x 9.8 m/s²) x sin (30)

F = 62.72 N