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3 years ago

In which situation is no work being done?

2 answers:

4 0

A and B
work = displacement*force
work is said to be done only when the force applied on the body makes the body move.
if force or displacement is zero than no work is being done
therefore in cases A and B no work is done

yawa3891 [41]3 years ago

4 0

Answer:

Work is said to occur when a force is able to cause displacement of an object in the direction of the applied force. It is given by the scalar product of force and displacement.

W = F.s = F s cos θ

Thus, no work is being done when no force is applied ( ∵ F = 0, W = 0) or the force does not result into displacement (∵ s = 0, F = 0) or when the force and displacement are perpendicular to each other (∵ θ =0, cos θ =0, W =0).

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1. Of the following, the one that is not an example of a suspension is

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Answer: 1. C

Explanation: 2. C

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4 years ago

A catapult with a radial arm 3.81 m long accelerates a ball of mass 18.2 kg through a quarter circle. The ball leaves the appara

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Answer:

(a) $\alpha = 53.73 m/s^2$

(b) I =428 $kgm^2$

(c) $\tau = 428 \times 53.73 = 22996 .44Nm$

Explanation:

GIVEN

mass = 18.2 kg

radial arm length = 3.81 m

velocity = 49.8 m/s

mass of arm = 22.6 kg

we know using relation between linear velocity and angular velocity

$\omega = \frac{v}{l}$

$\omega = \frac{49.8}{3.81} \\\omega = 12.99 rad/s$

for angular acceleration, use the following equation.

$\omega _{f}^2 = \omega_{i}^2+2\alpha\theta$

since $\omega _{i} = 0$

here for one circle is 2 π radians. therefore for one quarter of a circle is π/2 radians

so for one quarter $\theta = \frac{\pi }{2}$

$(12.99)^2 = 2\alpha(\frac{\pi }{2})$

on solving

$\alpha = \frac{168.74}{\pi }\\\alpha = 53.73 m/s^2$

(b)

For the catapult,

moment of inertia

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

$I = \frac{1}{2} \times 22.6\times 3.81 \times 3.81\I = 164kg m^2$

For the ball,

$I = MR^2$

$I = 18.2 \times 14.51$

$I = 264 kgm^2$

so total moment of inertia = 428 $kgm^2$

(c)

$\tau = I\alpha$

$\tau = 428 \times 53.73 = 22996 .44Nm$

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4 years ago

The main explanation for why heat pumps work is the ________ law of thermodynamics. Zeroth First Second

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Zeroth Law of thermodinamics

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4 years ago

Miss Piggy is exercising her vocal chords by matching the frequency f = 686 Hz of her speaker 4 m away. Where should Kermit sit

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Answer:

$z=\frac{2n+1}{8}$ for $n=0,1,2,3,...,15$

Where z=0 m is the position of Miss Piggy and z=4 m is the position of the speaker.

Explanation:

Assuming that Miss Piggy emits a sound wave that is in phase with the speaker, and that z=0 is the position of Miss Piggy and z=4 is the position of the speaker, we would have a superposition of two traveling sound waves. Furthermore let's assume that both waves have the same amplitude. The total resulting wave will be given by:

$\psi(t,z)=A\cos(\omega t-kz)+A\cos(\omega t +kz)$ where $\omega$ is the angular frequency of the traveling wave and $k$ is the wave number defined as $k=\frac{2\pi}{\lambda}$ . $\lambda$ is the wavelength of both traveling waves (they have the same wavelength because they have the same frequency). $\lambda=\frac{v}{f}$ where v is the speed of sound.

By using the trigonometric identity $2\cos(A)\cos(B)=\cos(A+B)+\cos(A-B)$ we can rewrite $\psi (t,z)$ as

$\psi (t,z)=2A\cos(\omega t)\cos(kz)$ .

In order for the resulting wave to have maximum destructive interference, that is to be zero for any time t, we need to have

$\cos(kz)=0$

$\implies kz=(2n+1)\cdot \frac{\pi}{2}\implies z=(2n+1)\frac{\pi}{2k}=(2n+1)\frac{\pi}{2}\frac{\lambda}{2\pi}=(2n+1)\cdot \frac{\lambda}{4}$

$\implies z=(2n+1)\cdot\frac{v}{4f}=\frac{2n+1}{8}$

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3 years ago

Which location focuses its use on a nonrenewable energy source? a wind mill farm a natural gas power plant a fruit orchard a com

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A <u>natural gas power plant</u> is a location that would focus its use on a non-renewable energy source.

<h3>What is non-renewable energy?</h3>

A non-renewable energy can be defined as an energy source that takes a very long time to be created or their creation happened long ago and isn't likely to happen again. Also, it is a type of energy source that is inexhaustible and irreplaceable.

<h3>The examples of non-renewable energy.</h3>

Some examples of non-renewable energy include the following:

Fossil fuel

Uranium

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Crude oil

Natural gas

In conclusion, a <u>natural gas</u><u> power plant</u> is a location that would focus its use on a non-renewable energy source.

Learn more about non-renewable energy here: brainly.com/question/26237167

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2 years ago