Answer:

Explanation:
Using the first law of thermodynamics:

Where
is the change in the internal energy of the system, in this case
,
is the heat tranferred, and
is the work,
with a negative sign since the work is done by the system.
From the previous equation we solve for heat, because it is the unknown variable in this problem

And replacing the known values:



The negative sign shows us that the heat is tranferred from the system into the surroundings.
They were formed in the nuclear<span> fusion reaction inside older </span><span>stars.
As a star burns, fusion reactions inside its core create heavier elements. Those materials are released when the star dies of old age in an explosion.</span>
<span>There is no special name for that. Physics is usually just concerned with "forces", and doesn't specify whether the force pushes or pulls. If you want to be more specific, you can just call it a "pulling force".
I hoped this was satisfying!:)</span>
Answer:
Acceleration, 
Explanation:
Given that,
Height from a ball falls the ground, h = 17.3 m
It is in contact with the ground for 24.0 ms before stopping.
We need to find the average acceleration the ball during the time it is in contact with the ground.
Firstly, find the velocity when it reached the ground. So,

u = initial velocity=0 m/s
a = acceleration=g

It is in negative direction, u = -18.41 m/s
Let a is average acceleration of the ball. Consider, v = and u = -18.41 m/s.

So, the average acceleration of the ball during the time it is in contact is
.
Reduce the friction. Since the total energy is conserved, the only way to improve its work capacity is by reducing energy that doesnt go into work.