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On the line of centres between the Earth and the Moon, there is a point where the net gravitational force is zero. Given that the distance between the two is 385,000 km, and that the Earth has a mass 81x that of the Moon, how far is this point from Earth?

Here, we must consider Newton's Law of Universal Gravitation. This states that the gravitational force acting between two bodies is proportional to the masses of each body and inversely proportional to the s...
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Answered by Phil R. • Physics tutor
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Describe the basic principles of ultrasound imaging (2 marks)

Ultrasound is any frequency above that of human hearing - around 20 kilohertz . Ultrasound imaging works by emitting a known intensity of ultrasound at a specific frequency, and capturing the reflected sound...
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Answered by Alex G. • Physics tutor
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Describe how the velocity and forces acting on a skydiver change during their fall (6 marks)

Different exam boards may want a different format of answer, so before beginning this question, it would be worth thinking how other six mark questions are marked in other papers. Edexcel want the student to...
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Answered by Jethro R. • Physics tutor
15685 Views

How does a hydraulic jack work and how do I work out the pressures involved?

(Draw hydraulic jack diagram using Pen tool) Firstly, we need the quation for pressure. Pressure is measured in Nm^2 which tells us that P=F/A. Where P is the pressure, F is the force in Newtons and A is the...
MZ
Answered by Max Z. • Physics tutor
6698 Views

What is the difference between a vector and a scalar?

A vector is a measurement of something that has more than 1 number associated with it, for example velocity. I can tell you how fast a car is going using the magnitude of velocity, speed, and I can tell you ...
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Answered by Max Z. • Physics tutor
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