Question

Question #ab539

Answer 1

`R=2.5*10^4N`.

Explanation:

The motion is a decelerated motion, so we can find the deceleration.

The two laws of the accelerated motion are:

`s=s_0+v_0t+1/2at^2`

and

`v=v_0+at`.

But if you solve the system of the two equations, you can find a third law really useful in those cases in which you haven't the time, or you haven't to find it.

`v^2=v_0^2+2aDeltas` in which `Deltas` is the space run.

So:

`a=(v^2-v_0^2)/(2Deltas)=(0^2-200^2)/(2*0.02)=-1000000m/s^2=-10^6m/s^2`,

so the resistence would be:

`R=m*a=2.5*10^-2Kg*(-10^6m/s^2)=-2.5*10^4N`.