4.98 kJ/mol would be the answer I believe :) hope this helped
Answer:
0.001 s
Explanation:
The force applied on an object is equal to the rate of change of momentum of the object:

where
F is the force applied
is the change in momentum
is the time interval
The change in momentum can be written as

where
m is the mass
v is the final velocity
u is the initial velocity
So the original equation can be written as

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:

Because they have special tool's that help them find out
We know that d=m/v where d is density, m is mass and v is volume. Lets transform formula to get v in times of d and m

Now we have to substitute our data to formula
V=

ml - its the answeer