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Question

I already did some question of a physics packet that i have for HW but I need help with some questions. Here they are.

1) Is the coefficient of friction lower when you walk on the slippery floor of the bumper cars or when you are walking on the pavement outside of the ride? How do you know?

2) Specifically, why does the person sitting on the outside of a high speed spinning ride, like Music Express , get crushed by the other people sitting with them?

3) It takes 20 seconds for the car to reach the top of freefall. If the tower is 30 meters tall , and we assume the car maintains a constant upward velocity, what is your velocity (speed) on Free Fall as it brings you to the top of the tower?

4) The sound of Batman can be heard throughout almost the entire theme park. Explain what causes the sound and how the sound travels to your ears.

Answer 1

Peopel just can't answer these too well, can't they? Anyway, here is my take:

1) You know the coefficient is lower on the slippery floor because you have to press down harder on each step to prevent yourself from slipping. Since the friction force to prevent your slipping is same, the frictional coefficient must be smaller with the greater normal force.

2) Because of Newton's first law, those in motion will stay in motion. All the people in the spinning car are moving off the car as dictacted in the law, but the car is trying to keep them inside. As the outermost person is being retained by the car, the rest of people in the car are trying to move off the car too. At this point, the outer person's body is keeping the rest of the people inside and that's why he/she is being 'squeezed'.

3) Since the car is moving at a constant speed, the velocity of the car as it approaches the top is v = 30 / 20 = 1.5 m/sec

4) It can take a long while to explain everything. The gist of it is this: Sound is caused by a vibrating device or devices that create waves in the air in all directions. The medium air then carries the sound energy to your ears, which translate into perception of sound. Here is more info if you need it:
http://en.wikipedia.org/wiki/Sound

I hope you are not just copying my answers, try to understand my answers and write them in your own words. Good luck.


XR

Answer 2

1) The coefficient of friction should be lower on the slippery floor, since it is designed to give less resistance to the cars in motion. The pavement will have higher resistance.

2) This is due to the centrifugal force of the person sitting on the inside on the person sitting on the outside.

4) http://www.madsci.org/posts/archives/Apr2003/1050876162.Eg.r.html

3) 30 m in 20 secs at constant velocity implies speed = 1.5 m/s. However at the top of the tower, I am asumming that the car will become stationary. Hence the speed should be zero.

Answer 3

1)tis less on the floor of bumper car coz tis well polished
2)tis due 2 inertia that pushes a thing outward
3)i dunno sry
4) its due 2 the resonance