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If an object moves in uniform circular motion in a circle of radius R = 1.0 meter, and the object takes 4.0 seconds to complete ten revolutions, calculate the centripetal acceleration.

Verified Answer :

a = ω²r

r = 1 m
ω = 2πf = 2π 10 / 4 = π5 s⁻¹

Answer:

\(a_c=246.5 \frac{m}{s^2}\)

Explanation:

The formula for centripetal acceleration is:

\(a_c=rw^2\)

Where,

\(r:\) radius.

\(w:\)Angular speed.

Angular speed is defined by:

\(w=\frac{\Delta\theta}{\Delta t}\)

Where,

\(\theta:\) position angle.

\(t:\) time.

In this case we have that the object takes 4.0 seconds to complete ten revolutions.

You have to know that 1 revolution = \(2\pi rad\), then

10 revolutions= \(10.2\pi rad = 20\pi rad\)

Replacing

\(\Delta\theta=20\pi rad\\\Delta t=4.0s\)

in the formula of Angular speed:

\(w=\frac{\Delta\theta}{\Delta t}\\\\w=\frac{20\pi rad}{4.0s}\)

\(w=5\pi \frac{rad}{s}\\w=15.7\frac{rad}{s}\)

Now we have,

\(a_c=rw^2\\a_c=r(15.7\frac{rad}{s})^2\)

r=1.0m

\(a_c=1.0m(15.7\frac{rad}{s})^2\\\\a_c=1.0(246.5)\frac{m}{s^2} \\\\a_c=246.5\frac{m}{s^2}\)

Then the centripetal acceleration is:

\(a_c=246.5 \frac{m}{s^2}\)