When you pedal a bicycle, maximum torque is produced when the pedal sprocket arms are in the horizontal position, and no torque is produced when they are in the vertical position. Explain

This is because when the pedal sprocket arms are in the horizontal position, it is perpendicular to the applied force, and the angle between the applied force and the pedal sprocket arms is 90⁰.  

Also, when the pedal sprocket arms are in the vertical position, it is parallel to the applied force, and the angle between the applied force and the pedal sprocket arms is 0⁰.

Explanation:

τ = r×F×sinθ

where;

τ is the torque produced

r is the radius of the pedal sprocket arms

F is the applied force

θ is the angle between the applied force and the pedal sprocket arms

Maximum torque depends on the value of θ,

when the pedal sprocket arms are in the horizontal position, it is perpendicular to the applied force, and the angle between the applied force and the pedal sprocket arms is 90⁰.

τ = r×F×sin90⁰ = τ = r×F(1) = Fr (maximum value of torque)

Also, when the pedal sprocket arms are in the vertical position, it is parallel to the applied force, and the angle between the applied force and the pedal sprocket arms is 0⁰.

τ = r×F×sin0⁰ = τ = r×F(0) = 0 (torque is zero).

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol  

b. a hockey puck sliding across the ice  

c. a compressed spring  

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice   is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice   is the correct option.