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1 year ago

A man runs at an average speed of 5.0m/s how long will it take him to run 5.2km on a perfectly straight line

Physics

1 answer:

Anni [7]1 year ago

8 0

The time taken is 1040 s.

<h3>What is speed?</h3>

The term speed refers to the rate at which the distance changes per unit time. This is why we define speed as the ratio of the distance to time for a body that is moving along a straight line.

Now;

We must first convert the distance to meters;

distance = 5.2km or 5200m

Speed = distance/time

time = distance/speed

time = 5200m/5 m/s

time = 1040 s

Learn more about speed:brainly.com/question/28224010

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Say that you are in a large room at temperature TC = 300 K. Someone gives you a pot of hot soup at a temperature of TH = 340 K.

DiKsa [7]

Answer:0.061

Explanation:

Given

$T_C=300 k$

Temperature of soup $T_H=340 K$

heat capacity of soup $c_v=33 J/K$

Here Temperature of soup is constantly decreasing

suppose T is the temperature of soup at any instant

efficiency is given by

$\eta =\frac{dW}{Q}=1-\frac{T_C}{T}$

$dW=Q(1-\frac{T_C}{T})$

$dW=c_v(1-\frac{T_C}{T})dT$

integrating From $T_H$ to $T_C$

$\int dW=\int_{T_C}^{T_H}c_v(1-\frac{T_C}{T})dT$

$W=\int_{T_C}^{T_H}33\cdot (1-\frac{300}{T})dT$

$W=c_v\left [ T-T_C\ln T\right ]_{T_H}^{T_C}$

$W=c_v\left [ \left ( T_C-T_H\right )-T_C\left ( \ln \frac{T_C}{T_H}\right )\right ]$

Now heat lost by soup is given by

$Q=c_v(T_C-T_H)$

Fraction of the total heat that is lost by the soup can be turned is given by

$=\frac{W}{Q}$

$=\frac{c_v\left [ \left ( T_C-T_H\right )-T_C\left ( \ln \frac{T_C}{T_H}\right )\right ]}{c_v(T_C-T_H)}$

$=\frac{T_C-T_H-T_C\ln (\frac{T_C}{T_H})}{T_C-T_H}$

$=\frac{300-340-300\ln (\frac{300}{340})}{300-340}$

$=\frac{-40+37.548}{-40}$

$=0.061$

4 0

3 years ago

A cylinder of mass 14.0 kg rolls without slipping on a horizontal surface. At a certain instant its center of mass has a speed o

aev [14]

Answer:

a) 567J

b) 283.5J

c)850.5J

Explanation:

The expression for the translational kinetic energy is,

$E_r = \frac{1}{2} mv^2$

Substitute,

14kg for m

9m/s for v

$E_r = \frac{1}{2} (14) (9)^2\\= 567J$

The translational kinetic energy of the center of mass is 567J

(B)

The expression for the rotational kinetic energy is,

$E_R = \frac{1}{2} Iw^2$

The expression for the moment of inertia of the cylinder is,

$I = \frac{1}{2} mr^2$

The expression for angular velocity is,

$w = \frac{v}{r}$

substitute

1/2mr² for I

and vr for w

in equation for rotational kinetic energy as follows:

$E_R = (\frac{1}{2}) (\frac{1}{2} mr^2)(\frac{v}{r} )^2$

$= \frac{mv^2}{4}$

$E_R = \frac{14 \times 9^2 }{4} \\\\= 283.5J$

The rotational kinetic energy of the center of mass is 283.5J

(c)

The expression for the total energy is,

$E = E_r + E_R\\\\$

substitute 567J for E(r) and 283.5J for E(R)

$E = 567J + 283.5\\= 850.5J$

The total energy of the cylinder is 850.5J

6 0

3 years ago

Read 2 more answers

Which of the following statements about galaxies is true? A. Galaxies typically contain millions of stars. B. Galaxies actually

Sloan [31]

the answer is D i took the quiz so it is definitely D

6 0

3 years ago

Read 2 more answers

Which of the following is an example of work being done on an object?

tensa zangetsu [6.8K]

Answer:

d. All of these

Explanation:

work is said to be done when a force is applied to an object through a certain distance. the SI unit of workdone is joules or newton per meter

mathematically

workdone = force x distance.

from the answers, work is being done because there is force applied in a certain distance.

from wagon is used to carry vegetables from a garden.
pulley is used to get water from a well.
hammer is used to remove a nail from a wall.

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4 years ago

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what is the geocentric model of stars and planets? a.) the belief that stars and planets revolve around the earth b.) the belief

amid [387]

a.) the belief that stars and planets revolve around the earth

Explanation:

The geocentric model of stars and planets is the belief that stars and planets revolves around the earth.

The model places the earth at the center of the system.

Geo - earth ; centric - center
This was the original school of thought about the way the earth relates to other bodies in the universe.
This model was replaced by the heliocentric universe in which stars are at the center and the planets revolves round them.
The idea was put forward by Nicola Copernicus

learn more:

Energy of the sun brainly.com/question/1140127

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7 0

3 years ago