Physics, 19.01.2021 18:50 katrinanuez

A swimmer bounces straight up from a diving board and falls feet first into a pool. She starts with a velocity of 3.00 m/s, and her takeoff point is 1.40 m above the pool. (a) How long are her feet in the air?
s
(b) What is her highest point above the board?
m
(c) What is her velocity when her feet hit the water?
m/s

Answers: 1

Show answers

Answers

Answer from: Paris4life

a) t= 0.92 s

b) h = 0.46 m

c) v = -6.04 m/s

Explanation:

In order to find the total time that the feet are in the air, we must add two times:1) time needed to reach to the maximum height (t₁) 2) time from when starts to fall from the maximum height until her feet hit the water (t₂)In order to get t₁, we need to take into account that at her highest point, the vertical speed will be zero.Taking for granted the value for the acceleration due to gravity,g = -9.8 m/s2, we can apply the definition of acceleration, and replacing by the givens, we can find t₁ as follows:

$t_{1} = \frac{v_{o}}{g} = \frac{3.0m/s}{9.8m/s2} = 0.3 s (1)$

In order to find t₂, we need to find first the highest point above the board, which is indeed what is asked for in b).We can use the following kinematic equation, taking into account that at the highest point, the final velocity vf will be zero.The equation can be written as follows:

$v_{f} ^{2} - v_{o} ^{2} = 2*g*\Delta h (2)$

Replacing by the givens, and solving for Δh, we get:

$\Delta h = \frac{v_{o}^{2}}{2*g} = \frac{(3.0m/s)^{2} }{2*9.8m/s2} = 0.46 m (3)$

The total height over the water will be just the sum of the takeoff point (1.40 m over the water) and the value we found in (3):H = 1.40 m + 0.46 m = 1.86 mNow, we can use the equation that relates the vertical displacement with the time, remembering that v₀=0, as follows:

$H = \frac{1}{2}*g*t^{2} (4)$

Replacing by the givens and the value found for H in (4), and solving for t, we get the value of t₂, as follows:

$t_{2} = \sqrt{\frac{2*H}{g} } = \sqrt{\frac{2*1.86m}{9.8m/s2} } = 0.62 s (5)$

The total time will the sum of t₁ and t₂:t = 0.3 s + 0.62 s = 0.92 s (6)

As we have just found, the highest point above the board was at 0.46m above the takeoff point, so the highest point above the board is just 0.46 m.

In order to find the velocity when her feet hit the water, we can use the same equation (2), taking into account that v₀=0, and Δh = H= -1.86m.Solving (2) for vf, we get:

$v_{f} = - \sqrt{2*g*H} = -\sqrt{2*9.8m/s2*1.86m} = -6.04 m/s (7)$

Answer from: Quest

this a false

explanation:

Answer from: Quest

can somebody give me the answer so i can graduate

Another question on Physics

Physics, 22.06.2019 09:00

This is really important 1.which of the following prefixes represents the largest value? (2 points)gigahectorkilomilli2.which of the following types of graphs is best for plotting the mean, median, and mode of data? (2 points)bar graphbox-and-whiskercircle graphstem-and-leaf

Answers: 1

Answer

Physics, 22.06.2019 10:30

Aperson gives a shopping cart an initial push along a horizontal floor to get it moving, and then lets go. the cart travels forward along the floor, gradually slowing as it moves. consider the horizontal force(s) on the cart while it is moving forward and slowing. which of the following statements is correct? (a) both a forward and a backward force are acting on the cart, but the forward force is larger. (b) only a forward force is acting which diminishes with time. (c) both a forward and a backward force are acting on the cart, but the backward force is larger. (d) only a backward force is acting, no forward force.

Answers: 3

Answer

Physics, 22.06.2019 14:40

Glass has a hardness that is in the middle of the hardness scale. what is the hardness of glass?

Answers: 1

Answer

Physics, 22.06.2019 22:20

A10-kg piece of aluminum sits at the bottom of a lake, right next to a 10-kg piece of lead, which is much denser than aluminum. which one has the greater buoyant force on it? explain. b - the aluminum a) both have the same buoyant force. b) the aluminum c) the lead d) it cannot be determined without knowing their volumes.

Answers: 1

Answer

You know the right answer?

A swimmer bounces straight up from a diving board and falls feet first into a pool. She starts with...

Questions