A Rock Is Whirled on the End of a String

question 9

Multiple Choice

A rock is whirled on the end of a string in a horizontal circle of radius R with a constant period T. If the radius of the circle is reduced to R/3, while the period remains T, what happens to the centripetal acceleration of the rock?

• A)The centripetal acceleration remains the same.
• B)The centripetal acceleration increases by a factor of 3.
• C)The centripetal acceleration increases by a factor of 9.
• D)The centripetal acceleration decreases by a factor of 3.
• E)The centripetal acceleration decreases by a factor of 9.

---

Definitions:

Long-Term U.S. Treasury Bonds

Government bonds issued by the United States Department of the Treasury with maturities typically longer than 10 years, providing stable income with low risk.

Risk Premium

The additional return over the risk-free rate that investors require as compensation for investing in risky assets.

Coefficient of Variation

A statistical measure of the dispersion of data points in a data series around the mean, expressed as a percentage of the mean, often used to assess the risk of an investment relative to its expected return.

Historical Excess Returns

The returns on an investment or portfolio in excess of a benchmark or risk-free rate, assessed over a specific historical period.