A grocery store employee pushes a loaded cart of mass along a level aisle
PHYSICS · Multi-part · CBSE · Physics · Laws of Motion · Laws of Motion
Problem
A grocery store employee pushes a loaded cart of mass 18kg along a level aisle. Rolling resistance from the wheels exerts a constant 15N force on the cart opposite the direction of motion. The employee wants the cart to speed up from rest so that, after a short time interval, it is accelerating at 1.2ms−2 straight ahead.
Ignore air resistance.
(a) Draw and label a free-body diagram for the cart while it is speeding up. List all external forces acting on the cart.
(b) Calculate the magnitude and direction of the net force required to achieve the stated acceleration.
(c) Determine the magnitude of the horizontal push force the employee must exert on the cart to produce the required net force.
(d) Suppose the employee can exert only 25N of horizontal force. Explain whether the desired acceleration can still be achieved and justify your answer with quantitative reasoning.