Uniform Circular Motion (quiz)

An object is moving in a circle. The velocity at any given moment is directed _______

tangent to the circle

A car makes a left-hand turn. The front seat passenger claims that she feels a sensation of being pulled outwards. This is best explained by the fact that

the passenger has a natural tendency to move tangent to and out of the circle

A ___ has both magnitude and direction. A _____ quantity has magnitude alone

vector, scalar

An object is moving in a circle of a radius at a constant speed. The acceleration of the object will INCREASE if

- Speed were increased - Its radius were decreased

At the bottom of one of the circular loops, the normal force of the pilot is

- directed upwards - of greater magnitude than the force of gravity

An object can move in a circle at constant speed and still have changing velocity. True or False?

True

When calculating the gravitational force between two extended bodies, you should measure the distance a. from the center of each body b. from the closest points on each body c. from the center of one body to the closest point on the other body d. from the most distant points on each body

a

Which of the following statements are true of an object moving in a circle at a constant speed? Select all that apply. a. The object is accelerating. b. The object is at equilibrium c. The velocity of the object is changing d. The direction of the object is changing e. The net force experienced by the object is 0 newtons.

a, c, d

The centripetal force on a object in circular motion is a. in the direction opposite the centripetal acceleration b. in the same direction as the centripetal acceleration c. in the direction opposite the tangential speed d. in the same direction as the tangential speed

b

What is the term for the net force directed toward the center of an object's circular path? a. centrifugal force b. centripetal force c. circular force d. orbital force

b

A centrifugal force is a. An outward force that must be present to move in a circle b. an inward force that causes objects to travel straight ahead c. a false force that we make up to explain our feelings of going straight

c

When an object is moving with uniform circle motion, the object's tangential speed a. is circular b. is directed toward the center of motion c. is perpendicular to the radius of the circle d. is perpendicular to the plane of motion

c

An object is moving in a circle at a constant speed of 30 m/s. It is known for sure that the object is accelerating because it is

changing the direction of its velocity

When an object is moving with uniform circular motion, the centripetal acceleration of the object a. is circular b. is perpendicular to the plane of motion c. is zero d. is directed toward the center of motion

d

Why does an astronaut weigh less on the moon than on Earth? a. The astronaut has less mass on the moon b. The astronaut is continually in free fall because the moon orbits Earth c. The astronaut is farther from Earth's center when he or she is on the moon d. The gravitational field strength is less on the moon's surface than on the Earth's surface

d

The paths of the planets about the sun are elliptical in shape, with the center of the sun being located at one focus. (The Law of Ellipses) An imaginary line drawn from the center of the sun to the center of the planet will sweep out equal areas in equal intervals of time. (The Law of Equal Areas) The ratio of the squares of the periods of any two planets is equal to the ratio of the cubes of their average distances from the sun. (The Law of Harmonies)

dsf

An object moves in a circle at a constant speed. The direction of the acceleration vector is best described as being

inwards, towards the center