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.
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<h2>Answer: B. Gravitational potential energy </h2>
Explanation:
<em>The gravitational potential energy is the energy that a body or object possesses, due to its position in a gravitational field. </em>
That is why this energy depends on the relative height of an object with respect to some point of reference and associated with the gravitational force.
In the case of the <u>Earth</u>, in which <u>the gravitational field is considered constant</u>, the value of the gravitational potential energy will be:
Where is the mass of the object,
the acceleration due gravity and
the height of the object.
As we can see, the value of is directly proportional to the height.