If Superman wants to slow down a fast car with speed 20 m/s and mass 1000 kg, how much force in N does he need to apply if he wants to get it down to zero within 3.2 seconds?

Force of 6250N is required to slow down the body to zero.

Explanation:

Speed(V)=20m/s

Initial speed (u) =0m/s

Mass(M)=1000kg

Time(t)=3.2seconds

Using first equation of motion to find the acceleration of the body:

V=U + at

20m/s=0 + a*3.2s

Therefore, a=(20m/s)/3.2s

a=6.25m/s^2

To find the force required to stop the body or get it down to zero:

Force(F)=mass x acceleration

F=(1000kg)*(6.25m/s^2)

F=6250N.

Therefore a force of 6250N is required to slow it down.

because if the tool that you are using is not balanced it there would be false mass.