A ball is held at a height H above a floor. It is then released and falls to the floor. If air resistance can be ignored, which
of the five graphs below correctly gives the mechanical energy E of the Earth-ball system as a function of the altitude y of the ball?
1 answer:
Answer:
Straight line graph attached showing mechanical energy on x-axis and altitude y on y-axis
Explanation:
As mechanical energy is the sum of kinetic energy and potential energy, the ball at a height H possesses potential energy= m.g.H
and Kinetic energy= 0.
But the sum of both energies is equal to m.g.H.
When the ball starts moving, the height starts to decrease and potential energy also decreases with decreasing y. On the other hand kinetic energy starts increasing with decreasing Y. But their sum remains constant i.e equal to mechanical energy. It remains same until the ball touches the ground. The graph attached shows height H or altitude y on x-axis and Mechanical Energy on y-axis. It shows a straight horizental line showing that mechanical energy remains same as y decreases.
You might be interested in
Answer:
<em>The second option has a lower power output. P=30 W</em>
Explanation:
<u>Mechanical Power </u>
It is a physical magnitude that measures the rate a work W is done over time t.
Since W=F.d
The first option means the worker will lift the box by a distance of 1.2 meters in 3 seconds by applying 250 N of force. That produces a power of
The second option requires the worker applies 75 N of force and travel a distance of 4 meters for 10 seconds, thus the power is
The second option has a lower power output