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Momentum is the quantity of motion of a moving object: its mass times its velocity, p = mv. This momentum calculator works it out in kg·m/s and also gives the kinetic energy.
Enter a stopping time to see the average force needed to bring the object to rest, from impulse = F × t = change in momentum. This is why catching a ball with soft hands, which increases the stopping time, hurts less.
| Mass (m) | 0.16 kg |
| Velocity (v) | 40 m/s |
| Time to stop (optional) | 0.01 s |
| Momentum (kg·m/s) | 6.4 |
| Kinetic energy (J) | 128 |
| Average stopping force (N) | 640 |
The ball has momentum 6.4 kg·m/s. Stopping it in 0.01 s takes an average force of 640 N.
Try this example →| Mass (m) | 1,000 kg |
| Velocity (v) | 20 m/s |
| Time to stop (optional) | 5 s |
| Momentum (kg·m/s) | 20,000 |
| Kinetic energy (J) | 200,000 |
| Average stopping force (N) | 4,000 |
Momentum is 20,000 kg·m/s; braking over 5 s needs an average force of 4,000 N.
Try this example →When two objects collide and no outside force acts, the total momentum before equals the total momentum after: m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂. Kinetic energy is only conserved too if the collision is perfectly elastic.
Momentum = mass × velocity, p = mv. The unit is kg·m/s, which is the same as N·s.
Impulse is force × time, and it equals the change in momentum. A longer stopping time means a smaller force.
Yes. It has the same direction as the velocity.
They increase the time over which a person's momentum drops to zero, which reduces the force on the body.