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Secure https://session.masteringphysics.com/myct/temview?assignmentProblemID-761283908offset next College Physics I with Lab Assignment Week 1 Problem 6 Part A Problem 6 What is the rock's velocity as it hits the bottom of the hole? Express your answer with the appropriate units. A rock is tossed straight up from the ground with a speed of 24 m/s. When it retums, itfalls into a hole 10 m deep. You may want to review (DA pages 51.54). For help with math skills, you may want to review: 39.0 m For general problem-solving tips and strategies for this Submit Hints My Answers Give up Review Part topic, you may want to view a Video Tutor Solution of Time in the air for a tossed ball. Incorrect; Try Again: s attempts remaining Part B How long is the rock in the air from the instant it is released until it hits the bottom of the hole? Express your answer with the appropriate units. t Value Units

Explanation / Answer

Taking as + ..
Initial vel u= 20m/s, a = -9.80m/s², displacement (final dist. from start) d = - 10m
(a)
v² = u² + 2ad
v² = 24² + (2 x -9.80 x -10) .. .. v = {576 + 196} .. .. .. v = 27.78 m/s

(b)
d = ut + ½ at²
-10 = (24t) + (½ x -9.80 x t²)
4.9t² - 24t - 10 = 0 .. a quadratic to solve (a=4.9, b=-24, c=-10)

t = 5.28 sec.

2) x = 1*(3^3) - 3(3) + 5 = 23 m

v = dx/dt = 3*3^2 - 3 = 24 m/s

a = dv/dt = 6t = 6*3 = 18 m/s^2

3) a) v = dx/dt = 12.5/10 = 1.25 m/s

b) v = 0 at t = 25, because displacement is zero

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