A person ran with a speed of 6 m/s onto the skateboard .What is the speed with which he ride on the skate board

First, remember the conservation of energy.

We can define the kinetic energy as:

K = (1/2)*m*v^2

where m is the mass, and v is the velocity.

The velocity of the person is 6m/s, and the mass is unknown.

Now, when the person rides the skateboard, this kinetic energy must remain constant, if M is the mass of the skateboard, the speed after the person rides ir will be:

K' = (1/2)*(m + M)*v'^2

Where v' is the new velocity.

In this case, we can suppose that the skateboard has really small mass compared with the person.

M < < m

then:

(m + M) ≈ m

then:

K' = (1/2)*m*v'^2 = K = (1/2)*m*v^2

from that equation, we can conclude that:

v' = v

Then if the velocity before riding the skateboard was 6m/s, then after would be also 6m/s.

diagram is missing, but i will try to explain your doubt.

answer:

amplitude is the maximum displacement or distance moved on a point of a vibrating body or wave measured from its equilibrium position.it is equal to half the length of vibration path.

kepler used the data from tycho blahe (his mentor) to construct the laws of planetary motion.