Answer:

Negative sign shows that velocity of the car is decreases at a constant rate
Explanation:
We have given velocity of the car is decreases from 32 m /sec to 24 m/sec in 4 second
So initial velocity of the car u = 32 m /sec
And finally car reaches to a velocity of 24 m/sec
Time taken to change in velocity = 4 sec
So final velocity v = 24 m/sec
From first equation of motion v = u+at
So 

Negative sign shows that velocity of the car is decreases at a constant rate
Answer:
0 m
Explanation:
Displacement is the shortest distance from one ppont to another. Here, the girl returns to the same spot after running. Hence, displacement is <u>0</u><u> </u><u>m</u>.
Newtons third law (inertia) is to blame
This question is poorly stated, but I assume you mean what conditions are needed. It would have to be cold outside, correct?
P = m x v
P = 30 x 10
=300