Answer:
21 Hz
Explanation:
The linear velocity is equal to
v = wr
Where w is the angular velocity and r is the radius.
Additionally, the angular velocity is equal to
w = 2πf
Where f is the frequency
So, replacing this equation on the equation above, we get:
v = (2πf)r
v = 2πrf
Therefore, the velocity and the frequency are proportional, so if the linear velocity is tripled, the frequency is tripled, so the new frequency will be
7 Hz x 3 = 21 Hz
So, the answer is 21 Hz
