Push the Box
How hard do you need to push a box to make it move? Choose a surface, set the mass and push force, and watch friction fight back.
- Speed
- 0.0 m/s
- Distance
- 0.0 m
- Time
- 0.0 s
- Acceleration
- 1.06 m/s²
The maths, live
Friction f = μ × m × gf = 0.3 × 20 × 9.81 = 58.9 NNet force F = Push − fF = 80 − 58.9 = 21.1 NNewton's 2nd law a = F ÷ ma = 21.1 ÷ 20 = 1.06 m/s²How it works
When you push a box, friction pushes back the other way. Friction depends on how rough the surface is (μ, the coefficient of friction) and how hard the box presses on the ground (its weight, m × g).
If your push is smaller than friction, the box stays still. If it is bigger, the leftover force (the net force) makes the box speed up. Newton's second law says the acceleration is the net force divided by the mass: a = F ÷ m.
Try this
- Find the smallest push that moves a 20 kg box on carpet.
- Double the mass. Do you need to double the push too?
- On ice, give the box a push and then set the force to zero. How far does it slide?