Two boxers are fighting. Boxer 1 throws his 5 kg fist at boxer 2 with a speed of 9 m/s.
Boxer 2 stops the punch with a force of 45,000 N.
How much time did it take for boxer 1's hand to stop moving?

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:

answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.

your answer is c! hope this : )