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What are the changes in energy that an object experiences when it is launched vertically at a given velocity into the air and falls back to the ground? This question ignores air resistance.

When the object is launched into the air it has a kinetic energy proportional to its velocity squared. As it travels its energy is converted into gravitational potential energy as it slows down due to the ef...
AH
Answered by Andrew H. • Physics tutor
2464 Views

A gold leaf electroscope with a zinc plate top is charged by briefly connecting it to the negative electrode of a high-voltage supply. Explain how the gold leaf will appear and how the leaf can be caused to drop again.

The gold leaf will diverge from the metal stem. This is because connecting the negative electrode to the zinc plate, causes an influx of electrons to flow into the electroscope. When the electrode is removed...
RN
Answered by Rebecca N. • Physics tutor
5348 Views

Calculate the gravitational force acting on the Moon, caused by the Earth, given that the masses of the Earth and the Moon are 6 x10^24 and 7.3 x10^22, respectively. The distance between the Earth and the Moon is 384 400 km.

The relevant equation to use in solving this problem, from Newton's law of gravitation, is Force = ( universal constant of gravitation x mass of earth x mass of moon)/ (distance between earth and moon square...
AS
Answered by Adam S. • Physics tutor
32413 Views

Why does gravitational potential energy have a negative value?

A point in a gravitational field has an associated gravitational potential. It is defined as the work done required to bring a unit mass from a point an infinite distance to that point in the field. At an in...
JP
Answered by Joseph P. • Physics tutor
4022 Views

Calculate the total resistance across AB; between A and B are two parallel branches, one branch with a 3 Ohm and a 5 Ohm resistor, the other branch with a 4 Ohm resistor.

1/Rt=1/R1+1/R2 R1=3+5=8 R2=4 Rt=1/(1/8+1/4)=8/3 Ohms = 2.67 Ohms (2 D.P.)
PA
Answered by Peter A. • Physics tutor
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