PHYSICS · Multi-part · CBSE · Physics · Laws of Motion · Laws of Motion
Problem
A 4.0kg box sits on a horizontal floor. A worker pushes on the box with a constant 30N force directed 35∘ below the horizontal. The coefficient of kinetic friction between the box and the floor is μk=0.25. The acceleration due to gravity is g=9.8ms−2.
(1) Part (a)
Draw a complete free-body diagram for the box, showing each force acting on it.
(2) Part (b)
Resolve the worker’s push into horizontal and vertical components and state the magnitude of each component.
(3) Part (c)
Determine the magnitude of the normal force exerted on the box by the floor.
(4) Part (d)
Calculate the magnitude of the box’s acceleration while it is being pushed.
(5) Part (e)
Some students incorrectly include both the original push vector and its perpendicular components on the same free-body diagram. Explain why this practice leads to an incorrect diagram, and describe the proper way to represent the forces in this situation.