a)
, 
The work done by the student in each trial is equal to the gravitational potential energy gained by the student:

where
m = 68 kg is the mass of the student
g = 9.8 m/s^2 is the acceleration of gravity
is the gain in height of the student
For the first student,
, so the work done is

The second student runs up to the same height (3.5 m), so the work done by the second student is the same:

2)
, 
The power exerted by each student is given by

where
W is the work done
t is the time taken
For the first student,
and
, so the power exerted is

For the second student,
and
, so the power exerted is

<span> The short answer is that they are not always weaker in fact. Some ionic compounds have very strong bonds, while some covalent bonds are quite weak. Usually however, it is easier to break an ionic bond than a covalent one. What determines the actual strength of a bond is quite complex, but let me try to explain the basic principles. this is the best answer i can come up with</span>
Answer:
space = 66.24 [m]
Explanation:
To solve this problem we must remember that the average speed is defined as the relationship between a space traveled over a certain time.

where:
space [m]
Av = average velocity = 3.6 [m/s]
time = 18.4 [s]
![space = 3.6*18.4\\space = 66.24 [m]](https://tex.z-dn.net/?f=space%20%3D%203.6%2A18.4%5C%5Cspace%20%3D%2066.24%20%5Bm%5D)
Answer:
if your in a car and you suddenly stop since you were in motion you fling forward while the car is stopped because an object in motion stays in motion unless it's stopped by an outside force and that's why we have seatbelts