Physics / Science
Explain changes in motion, work, energy and gravity.
A force is a push or pull that can change an object’s velocity or shape. Newton’s laws connect net force, mass and acceleration and explain how interacting objects exert equal and opposite forces.
Work is done when a force produces displacement. Energy is the capacity to do work and can appear as kinetic, potential, thermal or other forms while the total energy is conserved.
Worked example
A 4 kg box accelerates at 3 m/s². The resulting 12 N force moves it 5 m in the same direction. Find the force and work.
Answer The force is 12 N and the work done is 60 J.