1. Solve the general problem for the x-cm location, as measured from the left-most mass (m1). Check your text, to make sure you're right.
2. Use this to determine the location of the cm of the Earth/Moon system. Anything weird about this answer?
3. Look at the general expression for the cm of a rigid body. We'll delve into this in class.
4. Try these problem: ch.9 - 2, 4, if time do 3, 5, 6
Wednesday, February 29, 2012
Monday, February 27, 2012
HW
Finish elastic collision ramp problem from class
Also
1. Consider a typical force law for a sprng: F = k x
In this equation, x is displacement and k is a constant associated with how stiff the spring is (the opposite of how stretching it is)
Derive an expression for the work to stretch an "ideal" spring (one represented by the equation above). Note that this will also give you an expression for the energy stored in the stretched (or compressed) spring.
2. Try ch. 9 - 67, 69
Also
1. Consider a typical force law for a sprng: F = k x
In this equation, x is displacement and k is a constant associated with how stiff the spring is (the opposite of how stretching it is)
Derive an expression for the work to stretch an "ideal" spring (one represented by the equation above). Note that this will also give you an expression for the energy stored in the stretched (or compressed) spring.
2. Try ch. 9 - 67, 69
Monday, February 13, 2012
hw for Wednesday
1. Try to estimate the area under the curve shown here - it is the impulse of the engine. Watch units and note that each block has an area of 0.3 N-s
http://www.321rockets.com/estes-b6-0-model-rocket-engines-1608
Do this calculation independently so that can compare values.
(The impulse is supposedly around 5 N-s.)
2. Each of the two groups has time data. I doubt that it will be meaningful, but use the width of your index card (in whatever orientation you had it) to estimate the velocity of your car. I suspect that this will be on the low end of correct values. Either measure the index card width directly or take data from a standard index card, folded as you had done in class.
3. See page 222 in your text for the standard solutions to the elastic collision problem discussed in class.
4. Finally, catch up on these problems:
chapter 9 - 54, 61, 68
http://www.321rockets.com/estes-b6-0-model-rocket-engines-1608
Do this calculation independently so that can compare values.
(The impulse is supposedly around 5 N-s.)
2. Each of the two groups has time data. I doubt that it will be meaningful, but use the width of your index card (in whatever orientation you had it) to estimate the velocity of your car. I suspect that this will be on the low end of correct values. Either measure the index card width directly or take data from a standard index card, folded as you had done in class.
3. See page 222 in your text for the standard solutions to the elastic collision problem discussed in class.
4. Finally, catch up on these problems:
chapter 9 - 54, 61, 68
Tuesday, February 7, 2012
HW for this Thursday
Lab is due at the beginning of class.
We will try to launch horizontal rocket cars, to compare impulse to change in momentum.
We will try to launch horizontal rocket cars, to compare impulse to change in momentum.
Friday, February 3, 2012
today
Today
Sorry that I'm out. If anyone is absent, let Tracey B know.
Today, work on the lab - due 2 classes from today.
It should have:
Abstract
Your technique or method
Calculations
Percent difference between the initial velocities found by the 2 methods
Conclusion
I'll post a few homework problems later. Use this time for the lab now.
Thanks.
Sorry that I'm out. If anyone is absent, let Tracey B know.
Today, work on the lab - due 2 classes from today.
It should have:
Abstract
Your technique or method
Calculations
Percent difference between the initial velocities found by the 2 methods
Conclusion
I'll post a few homework problems later. Use this time for the lab now.
Thanks.
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