Question #ab539

1 Answer
Jun 13, 2015

#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#.