Push the crate (F = ma)

Push against friction and see the free-body diagram.

Push the crate

Interactive

net force0N

acceleration0m/s²

velocity0m/s

Your push F150 NMass m40 kg

Surface

Show all forces (free-body diagram)

The math, with your numbers

F_{\text{net}} = F_{\text{push}} + f = 150 + (-150) = 0\ \text{N}

a = \frac{F_{\text{net}}}{m} = \frac{0\ \text{N}}{40\ \text{kg}} = 0\ \text{m/s}^2

Friction: up to μs·N = 0.5 × 392 = 196 N before it slides; then μk·N = 118 N while sliding.

Try this

→On wood, push with 150 N on a 40 kg crate. Why doesn't it move? Find the push where it starts to slide.
→With no friction, push for a moment, then click 'Stop pushing'. What happens to the velocity?
→Keep the push the same and double the mass. What happens to the acceleration?

Want to know why it behaves like this?

The lesson “F = ma — Newton's Second Law” explains it step by step: How exactly does a force change motion?