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2 years ago

12

Explain the difference between cool air and warm air

1 answer:

Naddik [55]2 years ago

3 0

Answer: ok

Explanation:

The molecules in hot air are moving faster than the molecules in cold air. Because of this, the molecules in hot air tend to be further apart on average, giving hot air a lower density. That means, for the same volume of air, hot air has fewer molecules and so it weighs less.

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Which kind of energy does the soccer player transfer to the ball?

djyliett [7]

1. Kinetic

He makes the ball move by kicking it, which increases the kinetic energy

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3 years ago

A train station bell gives off a fundamental tone of 500 Hz as the train approaches the station at a speed of 20 m/s. If the spe

Brut [27]

Answer: 529.9 Hz

Explanation:

Here we need to use the Doppler equation, so we have:

f' = f*(v + v0)/(v - vs)

Here, f is the frequency = 500Hz

v is the velocity of the wave, = 334m/s

v0 is the velocity of the observer = 20m/s

vs is the velocity of the source = 0m/s

Then we have:

f' = 500Hz*(334m/s + 20m/s)/(334m/s) = 529.9 Hz

8 0

3 years ago

A uniform solid disk with a mass of 24.3 kg and a radius of 0.364 m is free to rotate about a frictionless axle. Forces of 90.0

a_sh-v [17]

Answer:

a. $-12.7 Nm$

b. $-7.9 rad/s^2$

Explanation:

I have attached an illustration of a solid disk with the respective forces applied, as stated in this question.

Forces applied to the solid disk include:

$F_1 = 90.0N\\F_2 = 125N$

Other parameters given include:

Mass of solid disk, $M = 24.3kg$

and radius of solid disk, $r = 0.364m$

a.) The formula for determining torque ( $T$ ), is $T = r * F$

Hence the net torque produced by the two forces is given as a summation of both forces:

$T = T_{125} + T_{90}\\= -r(125)sin90 + r(90)sin90\\= 0.364(-125 + 90)\\= -12.7 Nm$

b.) The angular acceleration of the disk can be found thus:

using the formula for the Moment of Inertia of a solid disk;

$I_{disk} = {\frac{1}{2}}Mr^2$

where $M$ = Mass of solid disk

and $r$ = radius of solid disk

We then relate the torque and angular acceleration ( $\alpha$ ) with the formula:

$T = I\alpha \\-12.7 = ({\frac{1}{2}}Mr^2)\alpha \\\alpha = -{\frac{12.7}{1.61}} = -7.9 rad/s^2$

4 0

3 years ago

Dmitry [639]

equal and opposite reaction.

5 0

3 years ago

Which of the following is a force acting between objects that do not touch?

kirill [66]

The answer is B friction force

3 0

3 years ago

Read 2 more answers