PHysics, circular motion?

1. You feel like you are flung sideways when your car travels around a sharp curve because





a) inertia keeps you moving in a straight line


b) there is centrifugal force acting on you


c) the car exerts an outward force on you


d) of gravity


2. When you observe an object moving in a circle, what can you infer?





a) there is a centrifugal force acting on the object


b) there is something pushing the object around the circle


c) a force towards the center is acting on the object


d) there are no net forces acting on the object


3. The moon is held in its orbit around the earth by





a) gravity


b) centrifugal force


c) the tides


d) the sun


4. Why does a car skid on an icy curve?











5. Why must there be a force acting in order for an object to successfully make it around a curved path?











6. If a car is going around a corner a centripetal force must be acting. How would the force be affected if:





a) the speed were doubled


b) the radius were doubled





c) both the speed and the radius were doubled





d) the speed was tripled





e) the radius was reduced to 1/4 the original











7. Below are a number of situations involving circular motion. In each case, identify the source of the force needed to keep the objects in question moving in their circular paths.





Example: A race car going around a corner:


Friction from the road holds the car in a circular path.





a) a child riding on a merry-go-round:











b) a ball at the end of a string being swung in a horizontal circle:











c) a sprinter running around the curve at the end of the track:











d) you in a car as you go over the top of a sharp bump:











e) you in your seat on a roller coaster going through the bottom of a dip:











f) a child being swung around in a horizontal circle by a well-meaning adult:











g) you in a car going around a horizontal corner:











h) you in the %26quot;Round-Up%26quot;, a carnival ride where you stand inside a spinning drum and are pressed against the side:











i) Mud sticking in the tread of a spinning automobile tire:











j) you turning on roller skates or roller blades:











k) water in a bucket being swung in a vertical circle:











l) Mars going around the sun:

PHysics, circular motion?
Aw, come on... seven questions?





Are you looking for homework help?





Good luck. You should be reading your books more. Ask your teacher for extra help.
Reply:You could have figured out the answers in the time it took to type the questions!





Some hints:


1) In Physics-speak, there is no such thing as %26quot;centrifugal force%26quot;. Interia is the reason that objects tend to move in the same linear direction.


2) In order for an object to maintain circular motion, there must be some force pulling the object towards the center of the rotation. This is called the centripetal force.


3) Something has to provide this centripetal force. If a toy is being whirled around on a string, this would be the string. For a car going around the curve, the cetripetal force is provided by the friction bewtween the tires in contact with the road.





Do yourself a favor and read your book! It%26#039;ll help come test time!



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