session.masteringphysics.com MasteringPhysics: Ch3 HW MasteringPhysics Constants

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session.masteringphysics.com MasteringPhysics: Ch3 HW MasteringPhysics Constants PHY-1103 Fall 2018 Cole KCh3 HW Problem 3.26 8 of 12 > Constants Part A Extreme-sports enthusiasts have been known to jump off the top of El Capitan, a sheer granite cliff of height 910 m in Yosemite National Park. Assume a jumper runs horizontally off the top of El Capitan with speed 4.0 m/s and enjoys a free fall until she is 40 m above the valley floor, at which time she opens her parachute (Figure 1) How long is the jumper in free fall? Ignore air resistance Express your answer using two significant figures and include the appropriate units IA 13 Seconds Figure 1 of 1> Submit Previous Answers Request Answer X Incorrect; Try Again; 6 attempts remaining 4.0 m/s Part B It is important to be as far away from the cliff as possible before opening the parachute. How far from the cliff is this jumper when she opens her chute? Express your answer using two significant figures and include the appropriate units

Explanation / Answer

Part A.

Vertical distance traveled before opening parachute = 140 - 910 = -770 m

Initial Velocity = 4 m/sec

Initial Horizontal Velocity = 4 m/sec

Initial Vertical Velocity = 0 m/sec

Vertical acceleration = -g = -9.8 m/sec^2

Using 2nd kinematic equation

H = U*t + 0.5*a*t^2

-770 = 0*t - 0.5*9.8*t^2

t = sqrt (770/(0.5*9.81)) = 12.53 sec

Now 12.53 sec should be 13 sec in 2 significant figure and your answer of 13 sec should be correct. Please ask your professor about this, as answer should be 13 sec.

You can try 12.5 sec OR 12 sec as the answer and see if that works.

Part B.

In this time horizontal distance traveled by jumper will be

R = V0x*t

Since there is no acceleration horizontal direction

R = 4*13 = 52 m

Again See that

If 12.5 sec works, than R = 4*12.5 = 50 m

If 12 sec works, than R = 4*12 = 48 m

Please Upvote.

Also Please Do not downvote until you get clarification from your professor. As Steps of my solution are correct.

Comment below if any of these values works.

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