Recent content by phyhelp

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    How Fast Do Toothbrush Bristles Move?

    Homework Statement 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) Homework Equations ω=Δθ/Δt v=rω The Attempt at a...
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    Time on Planet X: Solving for the Alignment of Clock Hands

    Thank you everyone for all your help!
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    Time on Planet X: Solving for the Alignment of Clock Hands

    I'm sorry but I'm still lost. Using the equation ω=θ/t, i solved for t when θ= 2∏ rad and ω= 4.27*10^-2 and 1.62*10^-2 and I got 147.147 s and 387.85 s, respectively. Am I on the right track?
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    Time on Planet X: Solving for the Alignment of Clock Hands

    Homework Statement A wall clock on Planet X has two hands that are aligned at midnight and turn in the same direction at uniform rates, one at 4.27×10−2 rad/ s and the other at 1.62×10−2 rad/s . At how many seconds after midnight are these hands first aligned and next aligned? Homework...