Question

please help

proof that potential energy = mgh

Answer 1

here it is.........

Suppose I let an object fall from rest for a distance hh. Given that the gravitational acceleration is gg the velocity of the object will be given by the SUVAT equation:

v2=u2+2ghv2=u2+2gh

In this case the initial velocity u=0u=0so we just get v2=2ghv2=2gh. The kinetic energy of the object is given by:

T=12mv2=12m(2gh)=mghT=12mv2=12m(2gh)=mgh

If energy is conserved the increase in kinetic energy must be equal to the decrease in potential energy, so we get:

ΔU=−ΔT=−mghΔU=−ΔT=−mgh

This tells us that if we lower the object by a distance hh the potential energy decreases by mghmgh, and conversely that if we raise it by a distance hh the potential energy increases by mgh

Answer 2

For the gravitational force the formula is P.E. = mgh, where m is the mass in kilograms, g is the acceleration due to gravity (9.8 m / s2 at the surface of the earth) and h is the height in meters. Notice that gravitational potential energy has the same units as kinetic energy, kg m2 / s2.