Please answer the question and show your working clearly.

1) Calculate the period of a 20Hz wave.
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2) An alternate current has a frequency of 50Hz, calculate the period.
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The position of a crate sliding down a ramp is given by x=(0.05t^3) m, y=(1.7t^2) m, z=(6−0.85t^5/2) m, where t is in seconds. (a) determine the magnitude of the crate's velocity when t = 2 s. (b) determine the magnitude of the crate's acceleration when t = 2 s.

How is zig zagging a form of acceleration?

How does an observation about an object differ from an inference about that object