Answer:
Centre of mass of any body is a point where all mass of a body is supposed to be concentrated
it lies in geometrical centre....
Energy can only be converted from one form to another
eg kinetic energy is converted to heat energy
The hang time of the student is 0.64 seconds, and he must leave the ground with a speed of 3.13 m/s
Why?
To solve the problem, we must consider the vertical height reached by the student as max height.
We can use the following equations to solve the problem:
<u>Initial speed calculations:</u>

At max height, the speed tends to zero.
So, calculating, we have:
<u>
</u>
<u>Hang time calculations:</u>
We must remember that the total hang time is equal to the time going up plus the time going down, and both of them are equal,so, calculating the time going down, we have have:

Then, for the total hang time, we have:

Have a nice day!
Answer:
P.E = 980 Joules
Explanation:
Given the following data;
Mass = 20 kg
Height = 5m
Acceleration due to gravity = 9.8 m/s²
To find the potential energy stored in the block;
Mathematically, potential energy is given by the formula;

Where,
P.E represents potential energy measured in Joules.
m represents the mass of an object.
g represents acceleration due to gravity measured in meters per seconds square.
h represents the height measured in meters.
Substituting into the equation, we have;

P.E = 980 Joules