Quiz

QUIZ

1. What is the relationship between the rotation angle, the arc length and the radius of a circle?

a. Rotation angle is directly proportional to the arc length and the radius of a circle. b. Rotation angle is directly proportional to the arc length and inversely proportional to the radius of a circle. c. Rotation angle is inversely proportional to the arc length and directly proportional to the radius of a circle. d. Rotation angle in inversely proportional to the arc length and the radius of a circle.

Answer: b. The rotation angle is directly proportional to the arc length and inversely proportional to the radius of a circle.

2. What is the number of radians in a complete revolution around a circle?

a. pi radians b. 0.5 pi radians c. 2 pi radians d. 2 pi squared radians

Answer: c. The totality of a circle or a complete revolution covers an angle that is considered to be 2-pi radians.

3. The greatest possible speed of a tire happens at a certain point at the rim of the tire. What is that speed called?

a. Arc speed b. Angular speed c. Tangential speed d. Linear speed

Answer: c. The tangential speed is the maximal speed of a circular object or tire, which is at the rim of the tire or the furthest out from the center of the circle.

4. What is the direction of the linear speed of an object going in a uniform circle?

a. Tangent to its path in the circle b. In a clockwise direction c. In a counterclockwise direction d. In either a clockwise or counterclockwise direction

Answer: a. When it comes to linear velocity, the velocity direction is considered tangential or a tangent to its path in the circle.

5. What is the relationship between centripetal acceleration in uniform movement around a circle to the radius of the circle?

a. Centripetal acceleration is proportional to the square of the radius. b. Centripetal acceleration is inversely proportional to the square of the radius. c. Centripetal acceleration is proportional to the radius. d. Centripetal acceleration is inversely proportional to the radius.

Answer: d. What this means is that, the smaller the radius or the tighter the turn around a circle, the greater is the acceleration. This is a linear inverse relationship.

6. How are the centripetal force and the mass of an object related?

a. Force is inversely proportional to the mass. b. Force is inversely proportional to the square of the mass. c. Force is directly proportional to the mass. d. Force is inversely proportional to the mass.

Answer: c. This is essentially no different from Newton’s second law. In the case of centripetal force, it is directly proportional to the mass of the object and acceleration of the object.

7. What is the direction of the centrifugal force?

a. In the direction of the path of the object in circular motion b. Toward the center of the circle of an object in circular motion c. Away from the center of the circle of an object in circular motion d. In the reverse direction of the path of an object in circular motion

Answer: c. Centrifugal force is a fictitious force that is pointed away from the path of an object in circular motion. It is based solely on the frame of reference and is felt by the person in an object or vehicle that is going in a circular motion.

8. What is the Coriolis effect?

a. The apparent curvature of a mass moving in a rotating system b. The actual curvature of a mass moving in a rotating system c. The outward direction of a mass leaving a rotating system d. The inward direction of a mass leaving a rotating system

Answer: a. This is the apparent curvature of a mass moving in a rotating system when it leaves the path of the system. It curves in a counterclockwise direction in a circle that is going clockwise but, as is clear, this is a fictitious curvature that occurs only within the frame of reference of the observer also rotating in the circle.

9. You have the mass of the earth and the mass of the moon that are attracted to each other. What is the difference between the force of gravity between the two objects if the moon has one percent of the mass of the earth?

a. The force of gravity is equal on the earth versus the moon b. There is only force from the earth c. There is 99 times more force of gravity from earth than there is from the moon d. The force of gravity on earth is 1 percent of the force of gravity on the moon

Answer: a. The force of gravity between the two would be equal, regardless of the mass. This must be the case according to Newton’s third law about equal and opposite forces. If they were not the same, the moon would escape earth’s orbit or the moon would crash into the earth.

10. What is the proportionality of the force of gravity between two objects of different masses and the radius between them?

a. The force is proportional just to the largest object and inversely proportional to the radius. b. The force is proportional to the mass of both bodies and inversely proportional to the radius. c. The force is proportional to just the masses of both bodies but not to the radius. d. The force is proportional to the masses of both bodies and inversely proportional to the square of the radius.

Answer: d. The force of gravity of two bodies is directly proportional to the masses of both bodies and inversely proportional to the square of the radius. There is a proportionality constant, which is about 6.7 x 1011 that is a part of this equation.