A worker must move a heavy wooden crate resting on a rough horizontal warehouse floor
PHYSICS · Multi-part · CBSE · Physics · Laws of Motion · Laws of Motion
Problem
A worker must move a heavy wooden crate resting on a rough horizontal warehouse floor. Two strategies are proposed:
• Method 1: Push on the crate with a force directed horizontally.
• Method 2: Pull on the crate using a rope that makes an angle θ above the horizontal.
Assume the magnitude of the applied force can be adjusted at will and that the coefficient of static friction between the crate and the floor is known.
Answer the following questions, using clear, complete sentences and appropriate physics vocabulary. Numerical calculation is not required.
(a) Draw separate free-body diagrams for the crate under Method 1 and Method 2, labeling all forces of interest.
(b) For each method, describe qualitatively how the magnitude of the normal force exerted by the floor on the crate depends on the applied force.
(c) Explain why one of the two methods can require a smaller applied force to initiate motion, and state the conditions (in terms of the angle θ) for which this advantage occurs.
(d) Suppose the rope were instead oriented at an angle ϕ below the horizontal while pulling. Predict how this change would affect the minimum applied force required to start the crate moving, and justify your prediction.