A 64.0-kg person holding two 0.900-kg bricks stands on a 2.00-kg skateboard. Initially, the skateboard and the person are at rest. The person now throws the two bricks at the same time so that their speed relative to the person is 19.0 m/s. What is the recoil speed of the person and the skateboard relative to the ground, assuming the skateboard moves without friction?

0.518 m/s

Explanation:

To solve this question, we would use the Law of conservation of momentum.

It is stated that the skateboard and the person were at rest initially, this means that their initial momentum is 0. Since they aren't moving.

And from the law if conservation of momentum, we know that initial momentum must be equal to final momentum.

The final momentum of the bricks will be 2* 0.9 * 19 = 34.2 kg m/s.

This means that the momentum of the person and that of the skateboard has to be 34.2 kg m/s also, although, it will be in the opposite direction.

Mass of the person plus that of the skateboard is

64 + 2 = 66 kg,

If we divide the momentum of the person and that of the skateboard by the mass of the both of them, we get the speed at which they are moving after the bricks are thrown

Recoil speed = (34.2 kg m/s)/(66 kg) = 0.518 m/s.

the order for strong to weak forces such as

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force

the fundamental forces are those forces that act between to objects or element to make interactions. there are four types of fundamental forces such as strong and weak nuclear forces (due to protons and electrons), electromagnetic force (due to the motion of electrons) and gravitational force (due to orbital movement of the planet). if these forces are arranged on the basis of their maximum strength then the order is

strong nuclear force → electromegnetic force → weak nuclear force → gravitational force