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Define energy, kinetic energy and potential energy. Prove
1
that kinetic energy is equal to -mv2 and potential energy is
2
equal to Mgh, where the letters have their usual meanings.
Answers
Answer:
Energy is the ability to do work. Potential Energy (PE) is stored energy due to position or state. PE due to gravity = m g h. Kinetic Energy (KE) is energy of motion.
Answer:
energy=the ability to be very active or do a lot of work without getting tired.
kinetic energy=energy which a body possesses by virtue of being in motion.
potential energy=the energy that is stored in an object due to its position relative to some zero position. An object possesses gravitational potential energy
Provethat kinetic energy is equal to -mv²/2
Consider an object of mass = m, uniform velocity = u and distance = s
Work done, (W) = F.s = ma.s …(1)
The work done on the object will cause a damage in its velocity. Let its velocity change from u to v.
v2 – u2 = 2as
image
Substituting the value of s in Eq. (1), we get
W = ma.s = image
Thus, work done is equal to the increase in kinetic energy.
potential energy is equal to Mgh,
If the object is lifted straight up at constant speed, then the force needed to lift it is equal to its weight mg. The work done on the mass is then W = Fd = mgh. ... When it does positive work it increases the gravitational potential energy of the system.