What is the maximum frictional force (in N) in the knee joint of a person who supports 45.0 kg of her mass on that knee if the coefficient of static friction is 0.016

Alfred pushes on a heavy box, but cannot move it. the box has a lot of inertia motion friction gravity

Arunner is training for an upcoming marathon by running around a 100-m-diameter circular track at constant speed. let a coordinate system have its origin at the center of the circle with the x-axis pointing east and the y-axis north. the runner starts at (x, y) = (50 m, 0 m) and runs 2.5 times around the track in a clockwise direction.

How do we measure or think of speed in the united states?