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What speed do satellites orbit at?

The key point to recognise here is that an object undergoing a circular orbit around the Earth is undergoing circular motion. Circular motion is caused by a centripetal force (acting towards the centre...

Answered by Ryan M. Physics tutor
3030 Views

Explain, in terms of the behaviour of molecules, how a gas exerts a pressure on the walls of its container. (4)

This question is 4 marks so you need to make at least 4 points.

These types of questions just require memorising the 4 points:

Lots of molecules collide with the walls.

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Answered by Jake F. Physics tutor
21112 Views

Two cars are crash tested. Car A has a crumple zone, B doesn't. Both cars have mass 1500kg and a driver of mass 80kg and crash at 20m/s. Cars A and B take 0.8 and 0.2 seconds to stop respectively. Using this information, are crumple zones a necessity? (6)

We need to show that car A is safer than car B and this is done by showing that the force is greater on car B than car A.

Start by finding the force on car A, total mass 1580kg:

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Answered by Jake F. Physics tutor
11144 Views

A lamp has a rating of 18V 9W. How much energy is transferred to the bulb in 5 minutes? Calculate the current through it when connected to a 18V supply.

The first question comes from the realisation that the power rating, "9W" represents 9 joules being supplied every second and so can be written as 9J/s and so in 5 minutes (o...

Answered by Alexander N. Physics tutor
3628 Views

Resistors of 5 ohms and 10 ohms are connected in series with a battery supplying 3 volts. What is the total resistance ? And calculate the current in the circuit.

For the first part of the question we note that the resistors are in series, this means we can simply add together the resistance, giving a value of:
15 ohms

For the second part we ...

Answered by Alexander N. Physics tutor
17677 Views

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