Recitation Worksheet D Solutions

# Recitation - Worksheet D Free fall and projectile motion 1 A person standing on a 3 m-tall elevator at rest tosses a coin vertically in the air The

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Worksheet D: Free fall and projectile motion. v 0 v e y y = 0 1. A person standing on a 3 m-tall elevator at rest tosses a coin vertically in the air. The coin leaves the person’s hand at 1.5 m from the elevator’s floor, with an initial speed of 4 m/s. Right at the same time, the elevator starts moving down at a constant speed of 1.5 m/s. a. Will the coin hit the ceiling or the floor of the elevator? How long after the coin was thrown will either happen? To see if the coin hits the ceiling, we will consider the motion of the coin and of the ceiling of the elevator. Let us take y = o at the position of the bottom of the elevator at t = 0. The positions as a function of time are: () 22 Ceiling: 3 m 1.5 m/s 1 Coin: 1.5 m 4 m/s 9.8 m/s 2 yt t =+ The coin hits the ceiling when they both have the same value of y. 2 3 1.5 1.5 4 4.9 0.48 s (the earliest time of the two solutions) tt t t −= + = This corresponds to y = 2.3 m So, yes, the coin hits the ceiling, because we were able to find the solution.

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## This homework help was uploaded on 03/27/2008 for the course PHYS 221 taught by Professor Herrera-siklody during the Fall '08 term at Iowa State.

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Recitation - Worksheet D Free fall and projectile motion 1 A person standing on a 3 m-tall elevator at rest tosses a coin vertically in the air The

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