All categories

2 years ago

A girl runs at a speed of 3.9 m/s off a high dive and hit the water 1.8 s later.

Physics

1 answer:

4vir4ik [10]2 years ago

7 0

Answer:

(a) the height of the diving board is 22.896 m

(b) the horizontal distance traveled by the girl is 7.02 m

Explanation:

Given;

initial speed of the girl, u = 3.9 m/s

time to hit the water, t = 1.8 s

(a) the height of the diving board is calculated as;

h = ut + ¹/₂gt²

h = (3.9 x 1.8) + ¹/₂ x 9.8 x 1.8²

h = 7.02 + 15.876

h = 22.896 m

(b) the horizontal distance traveled by the girl is calculated as;

X = ut

X = 3.9 x 1.8

X = 7.02 m

h = ut + ¹/₂gt²

h = 0 + ¹/₂gt²

2h = gt²

$t^2 = \frac{2h}{g} \\\\t = \sqrt{\frac{2h}{g} } \\\\t = \sqrt{\frac{2 \ \times\ 22.896 }{9.8} }\\\\t = 2.16 \ s$

Thus, if she had just dropped off the board, her time to drop to the water would have been longer.

You might be interested in

Minority group

Margarita [4]

Answer:

Minority group - People who are singled out for unequal treatment and who regard themselves as objects of collective discrimination.

Ethnicity - A shared identity based on cultural elements such as heritage, language, and religion.

Majority group - A group's subset that consists of more than half of the entire group's members.

Race - A socially constructed group of people who share physical characteristics that are considered significant by a society and that are used to distinguish them from other groups.

Explanation:

To better understand the above-mentioned definitions we would use some examples:

Elder people can be considered as a minority group in the United States because of their reduced status as a consequence of popular discrimination and prejudice against them. In contrast to them, young men consisting of more than half the population in the age category is an example of the majority group.

Groups of people like Hispanic Americans, Jews, Italian America, Irish are some examples of people belonging to different ethnic backgrounds residing in the U.S.

African Americans who are distinguished based on their skin color is an example of race.

6 0

2 years ago

In which one of the following situations is zero net work done? A) A ball rolls down an inclined plane. B) A physics student str

lidiya [134]

Answer:

Option D

Explanation:

The work done can be given by the mechanical energy used to do work, i.e., Kinetic energy and potential energy provided to do the work.

In all the cases, except option D, the energy provided to do the useful work is not zero and hence work done is not zero.

In option D, the box is being pulled with constant velocity, making the acceleration zero and thus Kinetic energy of the system is zero. Hence work done in this case is zero.

6 0

3 years ago

Read 2 more answers

An electron and a proton are held on an x axis, with the electron at x = + 1.000 m

mixas84 [53]

Answer:

r2 = 1 m

therefore the electron that comes with velocity does not reach the origin, it stops when it reaches the position of the electron at x = 1m

Explanation:

For this exercise we must use conservation of energy

the electric potential energy is

U = $k \frac{q_1q_2}{r_{12}}$

for the proton at x = -1 m

U₁ = $- k \frac{e^2 }{r+1}$

for the electron at x = 1 m

U₂ = $k \frac{e^2 }{r-1}$

starting point.

Em₀ = K + U₁ + U₂

Em₀ = $\frac{1}{2} m v^2 - k \frac{e^2}{r+1} + k \frac{e^2}{r-1}$

final point

Em_f = $k e^2 ( -\frac{1}{r_2 +1} + \frac{1}{r_2 -1})$

energy is conserved

Em₀ = Em_f

\frac{1}{2} m v^2 - k \frac{e^2}{r+1} + k \frac{e^2}{r-1} = k e^2 (- \frac{1}{r_2 +1} + \frac{1}{r_2 -1})

\frac{1}{2} m v^2 - k \frac{e^2}{r+1} + k \frac{e^2}{r-1} = k e²( $\frac{2}{(r_2+1)(r_2-1)}$ )

we substitute the values

½ 9.1 10⁻³¹ 450 + 9 10⁹ (1.6 10⁻¹⁹)² [ $- \frac{1}{20+1} + \frac{1}{20-1}$ ) = 9 109 (1.6 10-19) ²( $\frac{2}{r_2^2 -1}$ )

2.0475 10⁻²⁸ + 2.304 10⁻³⁷ (5.0125 10⁻³) = 4.608 10⁻³⁷ ( $\frac{1}{r_2^2 -1}$ )

2.0475 10⁻²⁸ + 1.1549 10⁻³⁹ = 4.608 10⁻³⁷ $\frac{1}{r_2^2 -1}$

$\frac{2.0475 \ 10^{-28} }{1.1549 \ 10^{-37} } = \frac{1}{r_2^2 -1}$

r₂² -1 = (4.443 10⁸)⁻¹

r2 = $\sqrt{1 + 2.25 10^{-9}}$

r2 = 1 m

therefore the electron that comes with velocity does not reach the origin, it stops when it reaches the position of the electron at x = 1m

4 0

2 years ago

a major difference radio waves, visible light, and gamma rays is the _________ of the photons, which results in different photon

Aleks04 [339]

There is a spectrum of electromagnetic radiation with variable wavelengths and frequency, which in turn imparts different characteristics. ... X-rays and gamma rays have the same nature as visible light, radiant heat, and radio waves; however, they have shorter wavelengths and consequently a larger photon energy.

3 0

2 years ago

Read 2 more answers

You are at the edge of a diving board that is 9 meters above the water. If you weigh 500 Newtons, what is your potential energy?

Semenov [28]

Answer:

4500 J

Explanation:

First, let's define some equations and derivations.

Our potential energy formula is:

$\displaystyle U = mgh$

Where m is mass (in kg), g is the gravitational constant (in m/s²), and h is height (in m).

We also know that mg is equal to the weight of an object (in N), from Newton's 2nd Law of Motion: F = ma (Force is equal to [constant] mass times acceleration).

Therefore, we can simply substitute force into the equation: