A group of students observes that a wooden block (m = 0.40 kg) on the end of a string with a radius of 0.7 meters makes 8 rotations in 20.7 seconds when twirled.
What is the block's tangential (linear) speed?
What is the block's angular speed?
2 answers
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You have this equation:
Velocity = 2pi x radius / T
So...
V = 2pi x 0.7 meters / (20.7 sec / 8 rotations)
That should give you the right answer. As a note, T, the time it takes to complete a period, has a unit of sec / rotation in this case, even if it may be more intuitive to calculate for rotations / sec (what I did before I realized that was wrong).
Velocity = 2pi x radius / T
So...
V = 2pi x 0.7 meters / (20.7 sec / 8 rotations)
That should give you the right answer. As a note, T, the time it takes to complete a period, has a unit of sec / rotation in this case, even if it may be more intuitive to calculate for rotations / sec (what I did before I realized that was wrong).
2 answers