Forces and their interactions

Show — 3 marks

A delivery driver pushes a cardboard box across a wooden warehouse floor. The box has a mass of 25 kg and experiences a friction force of 80 N opposing its motion. The driver applies a horizontal pushing force to move the box at constant velocity.

1. Show that the pushing force applied by the driver is 80 N. [1 mark]
2. The driver then pushes with a force of 120 N. Show that the resultant force on the box is 40 N in the direction of motion. [1 mark]
3. Using F = ma, show that the acceleration of the box is 1.6 m/s². (You may assume the friction force remains constant.) [1 mark]