Question

You have a cart with an iron block in it, all of which weighs 0.55 kg. You are trying to drag it across an unknown horizontal surface, by holding a force sensor scale that is attached to the cart with a string and pulling the scale and the cart along. YOu find that you have to pull with a force of 4.04 N before the cart will start moving, but after this, you only need to pull with a force of 2.57 N to keep it moving at a constant velocity.

a. Draw a force diagram labeling all the forces on the cart, just before it starts moving.

b. Would your force diagram in part A look different for the case where the cart is moving at a constant velocity, Explain.

c. Find the coefficients of static friction and kinetic friction.

d. For just the static case find the magnitude of the total force from the surface on the cart.

e. Consider a situation where the scale lets go of the cart, such that there is no longer a situation of constant velocity. Explain how the force of kinetic friction contributes to the motion.

Answer 1