All categories

2 years ago

A 70.0 kg person climbs stairs, gaining 3.90 meters in height. Find the work done (in J) to accomplish this task.

Physics

1 answer:

Veronika [31]2 years ago

6 0

Answer:

Work done, W = 2675.4 J

Given:

mass, m = 70.0 kg

height, H = 3.90 m

Solution:

According to the question, as the person jumps the stairs up, there is an increase in the potential energy of the person which is provided by the work done in climbing the stairs and is given by:

Work done, W = mgH

where

g = acceleration due to gravity = $9.8 m/s^{2}[tex][tex]W = 70.0\times 9.8\times 3.90 = 2675.4 J$

You might be interested in

What is the frequency of an electromagnetic wave that has a wavelength of 300,000 km? (the speed of light is 300,000 km/s.)?

expeople1 [14]

Frequency represents the number of complete oscillations in one second. it is measured in Hertz (Hz). Electromagnetic waves are waves which do not require a material media for transmission. They travel with a speed of light.
The speed (m/s) of a wave is given by frequency (Hz) × Wavelength (m)
Speed is 300,000 km/sec or 300,000,000 m/s and the wavelength is 300,000 km or 300,000,000 m.
Frequency = speed÷ wavelength
= 300000000 ÷ 300000000 = 1
Therefore, the frequency of the wave is 1Hz

6 0

3 years ago

The Bohr model below represents which answer Choice

Anton [14]

Answer:

Na⁺

Explanation:

In the given atom:

Number of protons = 11

Number of neutrons = 12

So, the number of electrons = 10

The number of protons within an atom is used to determine the kind of atom we have been given.

Since the number of protons is the same as the atomic number, here the atomic number is 11 and this is Sodium .

In this sodium atom, the number of protons is more than the number of electrons;

Charge = number of protons - number of electrons = 11 - 10 = +1

So, we have a Na⁺

4 0

3 years ago

8 cups water a day is that measuring cups?

Gwar [14]

No, it is 8 eight-once cups of water.
Hope it helps! :)

4 0

3 years ago

The human heart is a powerful and extremely reliable pump. Each day it takes in and discharges about 7500 L of blood. Assume tha

gregori [183]

The answers are:

a) $Work=125,923.61J$

b) $Power=1.46watt$

Why?

It seems that you forgot to write the questions of the problem, however, in order to help you, I will try to complete it.

The questions are:

a) How much work does the heart do in a day?

b) What is its power output in watts?

So, solving we have:

We need to convert from liter to cubic meters in order to use the given information, so:

$1L=0.001m^{3}\\\\7500L*\frac{0.001m^{3} }{1L}=7.5m^{3}$

Also, we need to find the mass given the density of the blood.

$1050}\frac{kg}{m^{3}}*7.5m^{3}=7875kg$

Now, calculating how much work does the heart do in a day, we have:

$Work=Fd=mgh\\\\Work=7875kg*9.81\frac{m}{s^{2}}*1.63m=125,923.61J$

Then, calculating what is the power output and its horsepower, we have:

$Power=\frac{Work}{time}\\\\Power=\frac{125,923.61J}{86,400s}=1.46watt$

Have a nice day!

7 0

3 years ago

Captain Jack Sparrow has been marooned on an island in the Atlantic by his crew, and decides to builda raft to escape. The wind

Marianna [84]

Answer:

d₃ = 37,729 km, θ= 5.1º North of West

Explanation:

This is a velocity addition problem, the easiest way to solve it is to decompose the velocities in a Cartesian system, the x-axis coincides with the West-East direction and the y-axis with the South-North direction

* first displacement is

d₁ₓ = 11 km

* second offset is

cos 6 = d₂ₓ / d₂

sin 6 = d_{2y} / d₂

d₂ₓ = d₂ cos 6

d_{2y} = d₂ sin 6

d₂ₓ = 6 cos 6 = 5.967 km

d_{2y} = 6 sin 6 = 0.6272 km

* third displacement is unknown

* fourth and last displacement

cos (-11) = d₄ₓ / d₄

sin (-11) = d_{4y} / d₄

d₄ₓ = d₄ cos (-11)

d_{4y} = d₄ sin (-11)

d₄ₓ = 21 cos (-11) = 20.61 km

d_{4y} = 21 sin (-11) = -4.007 km

They tell us that at the end of the tour you are back on the island, so the displacement must be zero

X axis

x = d₁ₓ + d₂ₓ + d₃ₓ + d₄ₓ

0 = 11 +5.967 + d₃ₓ + 20.61

d₃ₓ = -11 - 5.967 - 20.61

d₃ₓ = -37.577 km

Y axis

y = d_{1y} + d_{2y} + d_{3y} + d_{4y}

0 = 0 + 0.6272 + d_{3y} -4.007

d_{3y} = 4.007 - 0.6272

d_{3y} = 3.3798 km

This distance can be given in the form of module and angle

Let's use the Pythagorean theorem for the module

d₃ = $\sqrt{d_{3x}^2 + d_{3y}^2}$

d₃ = $\sqrt{37.577^2 + 3.3798^2}$

d₃ = 37,729 km

Let's use trigonometry for the angle

tan θ = d_{3y} / d₃ₓ

θ = tan⁻¹ $\frac{d_{3y}}{d_{3x}}$

θ = tan-1 (-3.3798 / 37.577)

θ = 5.1º

Since the y coordinate is positive and the x coordinate is negative, this angle is in the second quadrant, so the direction given in the form of cardinal coordinates is

θ= 5.1º North of West

3 0

2 years ago