Explanation:
Given that,
The initial velocity of a skater is, u = 5 m/s
She slows to a velocity of 2 m/s over a distance of 20 m.
We can find the acceleration of skater. It is equal to the rate of change of velocity. So, it can be calculated using third equation of motion as follows :

a = acceleration

So, her acceleration is
and she is deaccelerating. Also, her initial velocity is given i.e. 5 m/s.
1 ft²= 0.09290304m²
so:
43560ft²= 0.09290304m²×43560
= 4,046.8564224 m²
It is the last number minus 3
Mass=600kg
Velocity =15m/s
Momentum(p)=?
Now,
P=mass x velocity
=600x15
=9000kgm/s