A body is released from rest and allowed to fall freely from a given height under gravity. The kinetic energy at its half-way point is?
a little above half of its initial energy
a little below half of its initial energy
a half of its initial energy
a little above its initial energy
a little below its initial energy
Explanation
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Energy to get to the complete distance is 2 times(2*) the energy to get to half of the distance
Example:
if the mass is 10kg, the height is 10m and gravity is 10m/s^2
solution:
kinetic energy=potential energy
=mass*gravity*height
=10*10*10
kinetic energy=1000J
but for a distance half the 10m, the kinetic energy will be 500J
from the formula mgh = 1/2mv^2. when 'h' is halved all are divided by 2 eg. mg(h/2)=(mgh)/2
therefore, (mgh)/2=(1/2mv^2)/2.
in other words, when the height is halved, the whole formula is halved for PE. therefore KE is also halved.
just showing the algebraic side of solving.
At the beginning the kinetic energy is zero and the potential energy is maximum
In the middle the potential energy is half of the energy it had at the beginning and the kinetic energy is remaining half
Near the ground the potential energy is zero and the kinetic energy is Maximum
