1. Imagine that you’re sledding alone down a steep hill on a toboggan and that y

Question

1. Imagine that you’re sledding alone down a steep hill on a toboggan and that you left the top of the hill at the same time as an identical toboggan, loaded with 4 people.

a. Which toboggan will reach the bottom of the hill first?

b. If you took a toboggan down a 2% grade slope, for a 1000 foot run, and then you took the toboggan down a steeper route of 15% grade down the hill, how would that affect the speed of your descent? Explain.

c. Before each downhill run, you must pull the toboggan back to the top of the hill. If the Hill is 1000 vertical feet, how many runs will you do in 2 hours?

d. Why can you sled down a hill? But you can’t you skate down a hill?

e. How do snow shoes help you walk in snow? Why are their different sized snow shoes?

2.

a. Why is hip movement and turning the knees important in improving a golf swing?

b. During the back swing, are you accelerating?

c. At the moment you reach the bottom of the swing you make contact with the ball. Explain how energy is transferred from the club to the ball

d. Why is there more stress on a golfers shoulders at the start of the swing, than when hitting the ball?

e. Why do you need to follow through on the swing?

f. What has happened when a golf shot is hooked?

g. What is the sweet spot on a club and what does it do?

h. What is a ping sound and how is it produced when hitting a golf ball?

3. Diving boards and platforms offer a nearly ideal opportunity in which to experience the various laws of motion. When you jump off the high diving board, you are a falling object and, if you can keep your presence of mind as you fall, you will be demonstrating laws of physics. Imagine yourself diving off a platform 10 m above the water below.

a. If you walk very slowly off the platform, so that you fall directly downward, roughly how long will it take for you to reach the water?

b. You are part of a bad synchronized diving team with a friend. She walks slowly off the platform and you jump to give yourself a modest initial upward velocity. Who will reach the water first?

c. You change partners and now you leave the platform simultaneously with this new partner. Except he walks slowly off the platform, while you run off the platform. What direction is your initial velocity? Who will reach the water first?

d. If you walk very slowly off the platform, so that you fall directly downward, roughly how long will it take for you to reach the water if you were to fall off a 20 meter board?

e. How high would the board need to be for a 175 pound man to reach terminal velocity by the time he hit the water?

4. Advanced skiers turn by sliding the backs of their skis across the snow. Since the fronts of their skis don’t move much, the skis end up pointed in a new direction.

a. The amount of sideways force that a skier must exert on the skis to slide them sideways is proportional to how hard the skis press down on the snow beneath them. Why?

b. Less skilled skiers sometimes turn without unweighting—they push their skis sideways so hard that the skis slide anyway. This technique is exhausting. Why does it require so much work?

c. Why is wax used on skis? Why wouldn’t WD-40 work as well as the wax? What is in WD-40?

Explanation / Answer

Q1.
a) Neglecting the air resistance and friction both toboggan will reach the bottom at the same time because the downhill force pushes each toboggan caused by gravity and thus proportional to the mass of each toboggan. More mass will experience more downhill force and accelerate as fast as the one person and both will reach the bottom at the same time.

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