a-c please a swimmer bounces almost straight up from a diving board and Falls ve

Question

a-c please

a swimmer bounces almost straight up from a diving board and Falls vertically feet-first into a pool. She starts with a speed of 3.6 meters per second, and her take off point is 1.7 m above the pool surface.

Class Management Help Practice 11 Begin Date: 9/13/2017 12:00:00 AMDue Date: 11/30/2017 11:59:00 PM End Date: 12/4/2017 11:59:00 PM (14%) Problem 2: A swimmer bounces almost straight up from a diving board and falls vertically feet first into a pool. She starts with a speed of 3.6 m/s, and her takeoff point is 1.7 m above the pool's surface tus 33% Part (a) For how long are her feet in the air, in seconds? -.. 3300 Part (b) What is the height above the board, in meters, of her highest point? 33% Part (c) what is her velocity, in meters per second, when her feet hit the water? Assume the vertical component of the velocity is positive upwards Grade Summary Deductions 100% Potential us 0% pleted sino l cos() | tan() | | ( lidil 7 | 8 | 9 Submissions

Explanation / Answer

a] x = xo + vot - a*t^2 / 2

x = 1.70 + 3.6*t - (9.8/2)t^2 = 0

-4.9t^2 + 3.6t + 1.7 = 0

t = 1.06 s

Her feet are 1.06 s in the air

b] Highest point: maximum

dx/dt = d(1.70 + 3.6*t - (9.8/2)t^2 )/dt

x' = 3.6 - 9.8t = 0  

t = 3.6/9.8 = 0.367 s

x = 1.70 + 3.6*0.367 - (9.8/2)* 0.367^2

= 2.36 m

Her highest point above the board is 2.36 - 1.7 = 0.66 m (this is the point of her feet, so you should add her body hight for the real highest point)

c] v = vo - a*t

from a]. we know the t = 1.06 s when she hits the water:

v = 3.6 - 9.8* 1.06 = - 6.8 m/s

She's falling with a velocity of 6.8 m/s

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