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3 years ago

Work is done on an object only if the force and displacement are __________?

Physics

1 answer:

miskamm [114]3 years ago

8 0

It’s either movement or work or that’s what a quizzie said

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A sailcraft is stalled on a windless day. A fan is attached to the craft and blows air into the sail which bounces backward upon

mylen [45]

Answer:

Impulse = change in momentum w bounce

There are 2 impulses acting. Recoil of the fan going the negative direction and the impulse of the air bouncing off the sail. The greater impulse will bounce so the direction will be to the right moving the craft.

7 0

2 years ago

How much thermal energy is created in the slope and the tube during the ascent of a 30-m-high, 120-m-long slope?

charle [14.2K]

<span>The change in internal energy is only gravitional PE because the tube is being drug up at a constant speed. Since it is at a constant speed, the change in KE is 0. Change in PE = m*g*h = 78 kg * 10 m/s^2 * 30 m = 23400 J Work done on the system is from the force Work = force * distance = 350 N * 120 m = 42000 J So, work added 42000 J to the system, but the rider's energy only increased 23400 J. Therefore, friction took up the difference. Friction is where the thermal energy comes from Q = 42000 J - 23400 J = 18600 J. Therfore, friction generated 18600 J of heat to the surroundings.</span>

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3 years ago

Which describes Einstein’s idea of space and time?

Sholpan [36]

Time and space are both relative

8 0

3 years ago

Read 2 more answers

A man walks along a straight path at a speed of 4 ft/s. A searchlight is located on the ground 6 ft from the path and is kept fo

BARSIC [14]

We are given that,

$\frac{dx}{dt} = 4ft/s$

We need to find $\frac{d\theta}{dt}$ when $x=8ft$

The equation that relates x and $\theta$ can be written as,

$\frac{x}{6} tan\theta$

$x = 6tan\theta$

Differentiating each side with respect to t, we get,

$\frac{dx}{dt} = \frac{dx}{d\theta} \cdot \frac{d\theta}{dt}$

$\frac{dx}{dt} = (6sec^2\theta)\cdot \frac{d\theta}{dt}$

$\frac{d\theta}{dt} = \frac{1}{6sec^2\theta} \cdot \frac{dx}{dt}$

Replacing the value of the velocity

$\frac{d\theta}{dt} = \frac{1}{6} cos^2\theta (4)^2$

$\frac{d\theta}{dt} = \frac{8}{3} cos^2\theta$

The value of $cos \theta$ could be found if we know the length of the beam. With this value the equation can be approximated to the relationship between the sides of the triangle that is being formed in order to obtain the numerical value. If this relation is known for the value of x = 6ft, the mathematical relation is obtained. I will add a numerical example (although the answer would end in the previous point) If the length of the beam was 10, then we would have to

$cos\theta = \frac{6}{10}$

$\frac{d\theta}{dt} = \frac{8}{3} (\frac{6}{10})^2$

$\frac{d\theta}{dt} = \frac{24}{25}$

Search light is rotating at a rate of 0.96rad/s

4 0

2 years ago

Think of the last five things you read. Now think of a type of reading you havent done recenty

GarryVolchara [31]

Answer:

1) Half Girlfriend

2) I am Malala

3) Diamond fire

4)I too had a love story

5)Your Dream are Now Mine

Explanation:

I don't have a same pattern to read but mostly of romantic and fiction. I read less autobiographies but when I read I am Malala , it was an inspiring one.My favorite type of reading is romantic types and least favorite is non fiction especially History

6 0

3 years ago