Answer:
0.001 s
Explanation:
The force applied on an object is equal to the rate of change of momentum of the object:
[tex]F=\frac{\Delta p}{\Delta t}[/tex]
where
F is the force applied
[tex]\Delta p[/tex] is the change in momentum
[tex]\Delta t[/tex] is the time interval
The change in momentum can be written as
[tex]\Delta p=m(v-u)[/tex]
where
m is the mass
v is the final velocity
u is the initial velocity
So the original equation can be written as
[tex]F=\frac{m(v-u)}{\Delta t}[/tex]
In this problem:
m = 5 kg is the mass of the fist
u = 9 m/s is the initial velocity
v = 0 is the final velocity
F = -45,000 N is the force applied (negative because its direction is opposite to the motion)
Therefore, we can re-arrange the equation to solve for the time:
[tex]\Delta t=\frac{m(v-u)}{F}=\frac{(5)(0-9)}{-45,000}=0.001 s[/tex]
