Well, what do you think? Yes, C is nonsense. What about the other choices?abcd8989 said:Besides, while I am drilling for my exam, I find I don't know how to think of this conceptual past paper question:
A trolley travels with uniform velocity to the right on a horizontal ground and collides with a light helical spring attached to a wall fixed to the ground (earth). At the instant the trolley becomes momentarily at rest during collision, what has happened to the initial momentum of the trolley?
A. It has been transferred to the earth.
B. It has been stored in the spring.
C. It has been dissipated as sound and heat ( I guess this one is nonsence as only energy can be dissipated as sound and heat, right?)
D. It has been destroyed by the friction due to the ground.
For A and B, I am not sure which is correct. Both seem to be reasonable. For D, I also don't know whether momentum can be "destroyed", but I think it is not the answer. As it seems to be quite irrelevant with the question. The trolley stopped because all the KE is converted to elastic PE which is temporarily stored in the spring, but not stopped by "the friction due to the ground". However, I don't know whether "a little part of the momentum" has really been destroyed.Doc Al said:Well, what do you think? Yes, C is nonsense. What about the other choices?
How does one 'store' momentum?abcd8989 said:For A and B, I am not sure which is correct. Both seem to be reasonable.
No, momentum cannot be 'destroyed'. And there's no friction mentioned in the problem anyway.For D, I also don't know whether momentum can be "destroyed", but I think it is not the answer. As it seems to be quite irrelevant with the question. The trolley stopped because all the KE is converted to elastic PE which is temporarily stored in the spring, but not stopped by "the friction due to the ground". However, I don't know whether "a little part of the momentum" has really been destroyed.
Gravitational Potential Energy is the energy an object possesses due to its position in a gravitational field. It is the energy that is stored in an object when it is raised above the surface of the earth or any other planet.
Gravitational Potential Energy is calculated using the equation PE = mgh, where m is the mass of the object, g is the acceleration due to gravity, and h is the height of the object above the ground.
The relationship between Gravitational Potential Energy and height is directly proportional. This means that as the height of an object increases, its Gravitational Potential Energy also increases.
If an object is moved to a higher position, its Gravitational Potential Energy will increase, and if it is moved to a lower position, its Gravitational Potential Energy will decrease. This is because the height of the object changes, affecting the value of h in the PE = mgh equation.
Yes, Gravitational Potential Energy can be negative. This occurs when an object is at a position below the reference point, and its height is negative. In this case, the value of PE will be negative, indicating that the object has less energy than it would have at the reference point.