Question

Which of the following correctly describes the forces at work when you pedal a bike?

The force of gravity pulls your foot down, while force of friction pushes the pedal back at you.

The force of your foot pushing down on the pedal matches force of gravity pushing back upwards.

The force of your foot pushing on the pedal is matched by the force of the pedal pushing back on your foot.

The force of friction pushes down on the pedal, working in the opposite direction of gravity.

Answer 1

think about the pedal as the focus. then think about what forces are at play and how they direct there force on the pedal. F=ma so the key part is in what direction is the force accelerating the pedal.