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3 years ago

3. In which activity is no work done?

Physics

1 answer:

Firlakuza [10]3 years ago

6 0

Answer:

Sleeping, since your brain is working, but your physical body is not moving at all or moving rarely, therefore there is no work done in the activity of sleeping.

Explanation:

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Acceleration is defined as the rate of change for which characteristic?

Alenkasestr [34]

1) C. velocity

Acceleration is defined as the rate of change of velocity per unit time. In formulas:

$a=\frac{\Delta v}{\Delta t}$

where

$\Delta v$ is the change in velocity

$\Delta t$ is the time interval

Therefore, the correct answer is C. velocity.

2) A. 9.8m/s/s

Earth's gravity is a force, so it produces an acceleration on every object with mass located on the Earth's surface. This acceleration can be calculated, as it is given by the formula

$g=\frac{GM}{r^2}$

where

$G=6.67\cdot 10^{-11} m^3 kg^{-1} s^{-2}$ is the gravitational constant

$M=5.98\cdot 10^{24} kg$ is the Earth's mass

$r=6.37\cdot 10^6 m$ is the Earth's radius

By substituting these numbers into the formula, one can find that the acceleration due to Earth's gravity is $g=9.81 m/s^2$ .

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3 years ago

Read 2 more answers

What is the electric field strength 7.50 x 10E-1 meters from a 2.8 x 10 E-3 C charged object?

Nadusha1986 [10]

Answer:hi

Explanation:

5 0

3 years ago

Jake is helping Fin push a box at a constant velocity up an incline that makes an angle of 30.0° above the horizontal by applyin

andre [41]

Given data

The angle of inclination of the plane is theta = 30 degree

The applied force in the inclined plane is F = 94 N

The distance moved in the inclined plane is d = 2.30 m

The coefficient of kinetic friction is u_k = 0.280

The free-body diagram of the above configuration is shown below:

Here, the normal reaction force on the box is N, the acceleration due to gravity is denoted as g, the friction force on the box is F_f, and the mass of the box is denoted as m.

(a)

The expression for the work done by the pushing force is given as:

$W=Fd$

Substitute the value in the above equation.

$\begin{gathered} W=94\text{ N}\times2.30\text{ m} \\ W=216.2\text{ J} \end{gathered}$

Thus, the work done by the pushing force is 216.2 J.

(b)

The box is moving at the constant velocity, therefore, the pushing force will be equal to the frictional force and the component of the gravitational force in the inclined plane.

$\begin{gathered} F=F_f+mg\sin \theta \\ F=\mu_kN+mg\sin \theta \end{gathered}$

The expression for the normal reaction force is given as:

$N=mg\cos \theta$

The expression for the mass of the box is given as:

$\begin{gathered} F=\mu_k\times mg\cos \theta+mg\sin \theta \\ m=\frac{F}{\mu_kg\cos \theta+g\sin \theta} \end{gathered}$

Substitute the value in the above equation.

$\begin{gathered} m=\frac{94\text{ N}}{0.28\times9.8m/s^2\times\cos 30^o+9.8m/s^2\times\sin 30^0} \\ m=12.9\text{ kg} \end{gathered}$

Thus, the mass of the box is 12.9 kg.

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1 year ago

You open the refrigerator in your room and put in a case of room-temperature root beer. After an hour, the root beer is ice cold

agasfer [191]

Answer:

warmer

Explanation:

The law of conservation of energy tells us that energy cannot be created or destroyed, it can be transferred or converted from one from to another. In this question when the beer that is at room temperature is put in the fridge, it loses some heat energy. This heat energy is not destroyed, the fridge through multiple processes eventually releases this heat to the room through pipes at the back which is why they are normally warm. the heat from the food inside is expelled to the room. It is not lost.

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3 years ago

Alice and Bob are each riding horses on a carousel. Alice's horse is twice as far from the axis of spin of the carousel as Bob's

FromTheMoon [43]

Answer:

option (a)

Explanation:

the angular velocity of the carousel is same througout the motion, so the angular velocity of all the horses is same, but the linear velocity is different for different horses.

As the angular displacement of all the horses are same in the same time so the angular velocity is same.

The relation between the linear velocity and the angular velocity is given by

v = r ω

where, v is linear velocity and r be the distance between the horse and axis of rotation and ω be the angular velocity.

So, the angular velocity of Alice horse is same as the angular velocity of Bob horse.

ωA = ωB

Thus, option (a) is true.

8 0

3 years ago