Is mechanical energy can be negative???Explain how,since energy is a scalar quantity then why???
Asked by Ravikant
| 22nd Nov, 2015,
08:26: PM
Expert Answer:
Yes mechanical energy can be negative. Mechanical energy is the sum of potential as well as kinetic energy.
Negative sign in the energy does not have anything to do with the direction. Hence, being scalar has no bearing on the fact that energy cannot be negative.
The kinetic energy is always positive, but the potential energy can be negative.
Negative sign only indicates that the system is either bound or the reference point is taken such that potential energy is negative.
Answered by Romal Bhansali
| 23rd Nov, 2015,
10:50: AM
Concept Videos
- why is force attractive when the separation between body and force increases and potential increases and vice versa?
why is force repulsive when separation between body and force increases and potential decreases?
if PE/force is negative why attraction and if PE/force is positive why there is repulsion?
pls explain and prove the above points with suitable examples.
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- What is the source of the kinetic energy of the falling rain drop?
- Explain why the water at the foot of the waterfall is at different temperature from that at the top?
- A body is moving with the speed of 30 m/s. How high can it be lifted to gain an amount of potential energy equal to its kinetic energy. (Take g = 10 m/s2)
- A body falling from the height of 10 m rebounds from the hard surface. It loses 20% of its energy in impact. What is the height to which it would raise after the impact and where this energy goes after hitting the surface?
- Two springs have force constants k1 and k2 where k1 > k2. On which spring, more work is done if they are stretched by the same magnitude of force.
- If a block attached to a spring (whose one end is fixed) is pulled up to a distance xo and released, the amplitude of its motion cannot exceed
why?
- Draw a plot of spring force versus displacement x. Hence find an expression for the P.E of an elastic spring.
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