8. Centripetal Forces & Gravitation

Which of the following expressions correctly gives the centripetal acceleration of an object moving in a circle of radius $r$ with speed $v$?

A ball of mass $m$ is attached to a string and swung in a horizontal circle of radius $r$ at a constant speed $v$. What is the magnitude of the centripetal force acting on the ball? (answer in newtons)

A runner moves at a constant speed of $8.0m/s$ around the ends of a track that are semicircular with a radius of $12.5m$. What is her centripetal acceleration during the turn at each end of the track?

In which of the following sports does $centripetalforce$ play a key role in the motion of the participants?

Does the centripetal force acting on an object moving in a circular path do work on the object?

Which of the following is not an example of a centripetal force?

In the context of circular motion, which force is considered to be $\text{center seeking}$?

The Cosmo Clock 21 Ferris wheel in Yokohama, Japan, has a diameter of $100$ m. Its name comes from its $60$ arms, each of which can function as a second hand (so that it makes one revolution every $60.0$ s). Find the speed of the passengers when the Ferris wheel is rotating at this rate.

When a car moves through a curve on a flat road, what force provides the necessary $F\_c$ (centripetal force) to keep the car following the curved path?

Which of the following best describes the concept of $\mathrm{centripetal}\mathrm{force}$ in physics?

In uniform circular motion, can $a$_c (centripetal acceleration) change the speed of an object moving in a circle? Choose the best explanation.

Which of the following is a characteristic of centripetal acceleration?

A 2.0 kg pendulum bob swings on a 2.0-m-long string. The bob's speed is 1.5 m/s when the string makes a 15° angle with vertical and the bob is moving toward the bottom of the arc. At this instant, what are the magnitudes of the tension in the string?

Two wires are tied to the 2.0 kg sphere shown in FIGURE P8.45. The sphere revolves in a horizontal circle at constant speed. For what speed is the tension the same in both wires?

The Cosmo Clock 21 Ferris wheel in Yokohama, Japan, has a diameter of $100$ m. Its name comes from its $60$ arms, each of which can function as a second hand (so that it makes one revolution every $60.0$ s). What then would be the passenger's apparent weight at the lowest point?