Mechanics End of Unit Test Friday 22 March

We have nearly finished this topic and it is time to practise skills and develop exam technique

This homework exercise involves you tackling last years Mechanics paper with guidance. You need to follow instructions carefully

The resource materials for the questions in the 2012 paper are in the document below along with the equations you are required to use.

The questions are contained in the answer schedule at the end of this post. Because this is a larger set of questions than we usually tackle you may wish to draft out answers on paper before entering them on the answer schedule. If things go wrong you won’t have lost your information.

OK some assistance with the questions:

Question 1 The tractor

remember average speed involves the total distance

remember this is a distance time graph. Does the graph show a steady speed or an acceleration and what are the consequences for the forces acting on the tractor

In part c think about which equations you need to use. You are given mass and the question talks about net force. Speed is also changing. Select the equations you need and put the values in.

Part d is for experts who have covered pressure. You don’t need to tackle this question if you are unsure how to use the equation for pressure.

Question 2 the 100 meter race

This question is based on a speed time graph, what information do you get from this type of graph?

Part b, which equations equations will you need here. Think about acceleration, the force needed to produce it then work done

Question 3 Craters

This a question about gravitational potential energy and the kinetic energy it can be converted into. What are the factors which determine how much of this energy an object has. Look at the equation. Finally when an object falls, at the point of impact with the ground all the gravitational potential energy has been converted into kinetic energy.

You can do this test as many times as you wish till you get the grade you are satisfied with. Good luck

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Have a quick look at the video of Felix Baumgarten, a human with a huge amount of gravitational potential as he jumps from a platform slung beneath a balloon 39,000 meters above the earth’s surface.

Have a look  at the theory then tackle the questions at the end of this post.

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Watch the presentation carefully including the video then attempt the questions below. There will be a tutorial this Friday morning between 7.30 and 8.30 if you want more help.

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Try these questions to predict whether a molecule is polar or non polar.

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Only attempt this work if you have completed the homework in the post before this and want a tougher challenge

Read about the engineering problems associated with the bloodhound project and the attempt to beat the air speed record on the ground. Yes travel faster on the ground than we can travel in the air.

Now tackle some rudimentary engineering calculations using information about the car.

1. Calculate the average acceleration over 42 seconds. You will need to convert the speed to metric units.
2. Then calculate the unbalanced force that would produce this acceleration.
3. Estimate the average frictional forces opposing motion.
4. Discuss all the frictional forces, some are helpful some are not
5. Discuss any assumptions made when you calculate the average frictional forces opposing motion. Are they realistic?

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