The length of a bicycle pedal arm is 0.177 m, and a downward force of 145 N is applied to the pedal by the rider. What is the magnitude of the torque about the pedal arm's pivot when the arm is at an angle of (a)48.6°, (b) 90°, and (c) 180° with the vertical?

(a) 19.25 N-m

(b) 25.67 N-m

(c) 0 N-m

Explanation:

Given:

Length of the pedal arm (L) = 0.177 m

Downward force = 145 N

Magnitude of torque is given by the formula:

Where,

(a)

Given:

°

Therefore, torque is given as:

Therefore, the torque is 19.25 N-m.

(b)

Given:

°

Therefore, torque is given as:

Therefore, the torque is 25.67 N-m.

(c)

Given:

°

Therefore, torque is given as:

Therefore, the torque is 0 N-m.

you would expect a sound wave to speed up. - b)