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Explain why the moon is not pulled away from the Earth by the Sun.

The force of gravity decreases very rapidly with distance, since force is inversely proportional to distance 2 . The Sun is much further away from the Moon than the Earth, so its gravitational attraction isn...
AP
Answered by Alicia P. • Physics tutor
4112 Views

What is the current in a circuit?

The current is the rate of flow of charge. It is a measure of how many electrons pass a point over a certain amount of time. We measure current using an ammeter which gives current in Amps. Current is usuall...
EJ
Answered by Emma J. • Physics tutor
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Is momentum a vector quantity? Why?

Yes - Momentum is a vector quantity. A vector quantity possesses both a magnitude and direction. A scalar quantity possesses only a magnitude and no direction. Mass is an example of a scalar quantity (mass d...
HL
Answered by Harry L. • Physics tutor
52461 Views

A heater uses energy from a laptop computer to keep a mug of coffee hot. Energy is transferred to the coffee at the bottom of the mug. Explain how a convection current is set up in the coffee.

The molecules at the bottom of the mug gain energy and spread out as a result. This means that these molecules are less dense than the ones above them so they rise upwards. As they do so, they lose energy to...
EH
Answered by Evan H. • Physics tutor
4997 Views

A 10kg cube of iron with length 5cm is resting on a table surface. Assuming the acceleration under gravity of the block is 9.81ms^(-2), what is the pressure on the table?

Pressure is given by P=F/A, where F is force and A is area. Neither are given in the question, but A is the area of the cube in contact with the table; this is the area of one face of the cube, so A=L L=0.05...
WH
Answered by William H. • Physics tutor
4268 Views