# Test 3 Physics

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1.
1 point
Water settles to the bottom of a tank of gasoline. Which takes up more space: 1 kg of water or 1 kg of gasoline?
2.
1 point
A marshmallow is filled with air bubbles. Why does a marshmallow puff up when you toast it?
3.
1 point
Why does hot maple syrup pour more easily than cold maple syrup?
4.
1 point
Why does a relatively modest narrowing of the coronary arteries, the blood vessels supplying blood to the heart, cause a dramatic drop in the amount of blood flowing through them?
5.
1 point
A barometer, which is often used to monitor the weather, is a device that measures air pressure. How could you use a barometer to measure your altitude as you climbed in the mountains?
6.
1 point
A helium-filled balloon floats in air. What will happen to an air-filled balloon in helium? Why?
7.
1 point
Many jars have dimples in their lids that pop up when you open the jar. What holds the dimple down while the jar is sealed, and why does it pop up when the jar is opened?
8.
1 point
Explain why a parachute slows your descent when you leap out of an airplane.
9.
1 point
A hurricane or gale force wind can lift the roof off a house, even when the roof has no exposed eaves. How can wind blowing across a roof produce an upward force on it?
10.
1 point
Why must the pressure inside a whistle teakettle exceed atmospheric pressure before the whistle can begin to make noise?
11.
1 point
Pedestrians on the surface of a windswept bridge don’t feel the full intensity of the wind because the air is moving relatively slowly near the bridge’s surface. Explain this effect in terms of a boundary layer.
12.
1 point
To drive along a level road at constant velocity, your car’s engine must be running and friction from the ground must be pushing your car forward. Since the net force on an object at constant velocity is zero, why do you need this forward force from the ground?
13.
1 point
When you mix milk or sugar into your coffee, you should move the spoon quickly enough to produce turbulent flow around the spoon. Why does this turbulence aid mixing?
14.
1 point
Many grocery stores display frozen foods in bins that are open at the top. Why doesn’t the warm room air enter the bins and melt the food?
15.
1 point
A baker is decorating a cake by squeezing frosting out of a sealed paper cone with the tip cut off. If the baker makes the hole at the tip of the cone too small, it’s extremely difficult to get any frosting to flow out of it. Why?
16.
1 point
When a fish is floating motionless below the surface of a lake, what is the amount and direction of the force the water is exerting on it?
17.
1 point
When you swing a stick slowly through the air, it’s silent, but when you swing it quickly, you hear a “whoosh” sound. What behavior of the air is creating that noise?
18.
1 point
If you seal a soft plastic bottle or juice container while hiking high in the mountains and then return to the valley, the container will be dented inward. What causes this compression?
19.
1 point
Ice tea is often dispensed from a large jug with a faucet near the bottom. Why does the speed of tea flowing out of the faucet decrease as the jug empties?
20.
1 point
If you start two identical paper boats from the same point, you can make them follow the same path down a quiet stream. Why can’t you do the same on a brook that contains eddies and vortices?
21.
1 point
You use your breath to inflate a large rubber tube and then ride down a snowy hill on it. After a few minutes in the snow the tube is underinflated. What happened to the air?
22.
1 point
How would a Frisbee fly on the airless moon?
23.
1 point
Each time you breathe in, air accelerates toward your nose and lungs. How does the pressure in your lungs compare with that in the surrounding air as you breathe in?
24.
1 point
A favorite college prank involves simultaneously flushing several toilets while someone is in the shower. The cold water pressure to the shower drops and the shower becomes very hot. Why does the cold water pressure suddenly drop?
25.
1 point
You seal a rigid container that is half full of hot food and put it in the refrigerator. Why is the container’s lid bowed inward when you look at it later?
26.
1 point
A log is much heavier than a stick, yet both of them float in water. Why doesn’t the log’s greater weight cause it to sink?
27.
1 point
When you stand in a pool with water up to your neck, you find that it’s somewhat more difficult to breathe than when you’re out of the water. Why?
28.
1 point
If you ride your bicycle directly behind a large truck, you will find that you don’t have to pedal very hard to keep moving forward. Why?
29.
1 point
Why must tall dams be so much thicker at their bases than at their tops?
30.
1 point
In 1971, astronaut Alan Shepard hit a golf ball on the moon. How did the absence of air affect the ball’s flight?