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3 years ago

An object with a mass of 21 kilograms is lifted through a distance of 7 meters how much work is done

1 answer:

4 0

We have: W = F × s
W = m×g×s
Here, m = 21 Kg [ Given ]
g = 9.8 m/s² [ constant value for earth system ]
s = 7 , [ Given ]

Substitute their values into the expression:
W = 21×9.8×7
W = 1440.6 Joules

In short, Your Final Answer would be 1440.6 J

Hope this helps!

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Which explanation best describes a wave?

Gekata [30.6K]

Answer:

C. a disturbance that travels through a medium with a transfer of energy and without a transfer of matter

Explanation:

A wave is any disturbance that transfers energy from one location to the other via a substance called medium. It is important to note that a wave only conveys energy and not matter. For example, sound wave is a type of wave that carries sound energy from one place to another via mediums such as water, air etc.

Hence, according to this question, a wave can be described as a disturbance that travels through a medium with a transfer of energy and WITHOUT A TRANSFER OF MATTER.

5 0

3 years ago

A wheel has a rotational inertia of 16 kgm2. Over an interval of 2.0 s its angular velocity increases from 7.0 rad/s to 9.0 rad/

german

Answer:

<h2>128.61 Watts</h2>

Explanation:

Average power done by the torque is expressed as the ratio of the workdone by the toque to time.

Power = Workdone by torque/time

Workdone by the torque = $\tau \theta$ = $I\alpha * \theta$

I is the rotational inertia = 16kgm²

$\theta = angular\ displacement$

$\theta = 2 rev = 12.56 rad$

$\alpha \ is \ the\ angular\ acceleration$

To get the angular acceleration, we will use the formula;

$\alpha = \frac{\omega_f^2- \omega_i^2}{2\theta}$

$\alpha = \frac{9.0^2- 7.0^2}{2(12.54)}\\\alpha = 1.28\ rad/s^{2}$

Workdone by the torque = 16 * 1.28 * 12.56

Workdone by the torque = 257.23 Joules

Average power done by the torque = Workdone by torque/time

= 257.23/2.0

= 128.61 Watts

8 0

3 years ago

The greatest obstacle to developing solar energy is _____. lack of sunlight at high latitudes lack of sunlight at night lack of

KATRIN_1 [288]

The correct answer is option #4. The greatest obstacle to developing solar energy is large areas required to collect sufficient energy. Solar energy is the energy that is the sun is producing and being converted into thermal energy that can be used for everyone's daily lives.

3 0

3 years ago

Read 2 more answers

Two loudspeakers emit identical sound waves along the x-axis. The sound at a point on the axis has maximum intensity when the sp

EleoNora [17]

The concept required to solve this problem is related to the wavelength.

The wavelength can be defined as the distance between two positive crests of a wave.

The waves are in phase, then the first distance is

$\Delta x_1 = 20cm$

And out of the phase when

$\Delta x_2 = 30cm$

Thus the wavelength is

$\Delta x_2-\Delta x_1 = \frac{\lambda}{2}$

Here,

$\lambda =$ Wavelength

If we rearrange the equation to find it, we will have

$\lambda = 2 (\Delta x_2-\Delta x_1 )$

$\lambda= 2(30-20)$

$\lambda = 20cm$

Therefore the wavelength of the sound is 20cm.

5 0

4 years ago

dado los vectores a=3.5 b=4 c=6.5 , si se sabe que a+b+c=0 (resultante) cual es el angulo formado por A y B?

lawyer [7]

cos(A) = (b2 + c2 − a2) / 2bc = (16+6.5^2-3.5^2)/(2*4*6.5) = 0.88461538 so A = cos−1 (0.88461538) = 27.79 Deg cos(B) = (c2 + a2 − b2)/2ca = (3.5^2+6.5^2-16)/(2*3.5*6.5) = 0.84615385 so B = cos−1 (0.84615385) = 32.2 Deg

6 0

3 years ago