Electric toothbrushes can be effective in removing dental plaque. One model consists of a head 1.10 in diameter that rotates back and forth through a 70.0angle 7600 times per minute. The rim of the head contains a thin row of bristles. (See the figure .)

Using your own observations, what is the approximate speed of the bristles against your teeth when you brush by hand with an ordinary toothbrush? (Estimate that the toothbrush turns back and forth through 45° five times per second) PLEASE HELP! I've used v=rw and get a wrong anwer :(

Question

Electric toothbrushes can be effective in removing dental plaque. One model consists of a head 1.10 in diameter that rotates back and forth through a 70.0angle 7600 times per minute. The rim of the head contains a thin row of bristles. (See the figure .)

Using your own observations, what is the approximate speed of the bristles against your teeth when you brush by hand with an ordinary toothbrush? (Estimate that the toothbrush turns back and forth through 45° five times per second) PLEASE HELP! I've used v=rw and get a wrong anwer :(