Give it a push
Force & friction
Balance a push against friction and discover when a block starts sliding.
Force & frictionTRY IT YOURSELF
Friction14.715 N
Net force5.285 N
Acceleration1.057 m/s²
StateSliding
Teal + amber · follow the changing valuesIdealized physics model
What if you changed…
Try a starting point
Find the smallest push that overcomes static friction.
See the calculation
Fnet = ma · fs ≤ μsN · fk = μkN
- Normal force N = mg = 5 × 9.81 = 49.05 N.
- Maximum static friction = μN = 14.71 N. Actual opposing friction = 14.71 N.
- Net force = 20 − 14.71 = 5.29 N. Acceleration = Fnet/m = 1.06 m/s².
What this model assumes
Horizontal surface, rightward applied force, g = 9.81 m/s². For comparison, static and kinetic coefficients both equal μ. The block starts at rest.
Keep an eye on this
Static friction is not always μsN. That expression gives its maximum value.
Understand the physics ↗A little question. A clearer picture.
Force & friction: common questions
Wondering about the why? Start here.
Why is the block not moving with a small force?
Static friction balances the applied force while the force is at or below its maximum. The net horizontal force is then zero.
Why do the force arrows use the same scale?
A shared arrow scale lets you compare opposing forces. Equal arrows mean zero net force; their difference determines acceleration.