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2 years ago

A leaf falls from a tree. As you are watching the leaf fall, how can you tell that it has reached its terminal velocity?

1 answer:

5 0

You can tell that it has reached its terminal velocity when D) the leaf is falling with a constant velocity as you are watching the leaf fall. The terminal velocity is a point of condition when an object's speed equalize the force of gravity. The terminal velocity condition could occur if there is no acceleration to the object's speed.

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X-rays are used instead of visible light because X-rays have shorter ______________ than visible light, allowing them to produce

Novay_Z [31]

X-rays have shorter wavelength than visible light. But that's hardly the reason that they're used for medical imaging. xrays have much higher frequencies then visible light which means they have much greater penetrating ability. with xrays you can see inside the body. you can't do that with a visible flashlight no matter how bright and powerful it is.

4 0

3 years ago

Read 2 more answers

Newton's first law of motion states that an object will keep a constant speed and direction unless acted upon by an unbalanced f

trasher [3.6K]

Answer:

The unbalanced force that caused the ball to stop was friction

Explanation:

As Newton's second law states, the acceleration of an object is proportional to the net force applied on the object:

$F=ma$

therefore, in order to move at constant speed, an object should have a net force of zero (balanced forces) acting on it.

In this case, the ball slows down and eventually comes to a stop: it means that the ball is decelerating, so there are unbalanced forces (net force different from zero) acting on it. The unbalanced force acting on the ball is the friction: friction is a force against the motion of the object, which is due to the contact between the surface of the ball and the surface of the street, and this force is responsible for slowing down the ball.

3 0

3 years ago

Read 2 more answers

During the spin cycle of a washing machine, the clothes stick to the outer wall of the barrel as it spins at a rate as high as 1

Darya [45]

To answer the two questions, we need to know two important equations involving centripetal movement:

v = ωr (ω represents angular velocity in radians)

a = $\frac{v^{2}}{r}$

Let's apply the first equation to question a:

v = ωr

v = ((1800*2π) / 60) * 0.26

Wait. 2π? 0.26? 60? Let's break down why these numbers are written differently. In order to use the equation v = ωr, it is important that the units of ω is in radians. Since one revolution is equivalent to 2π radians, we can easily do the conversion from revolutions to radians by multiplying it by 2π. As for 0.26, note that the question asks for the units to be m/s. Since we need meters, we simply convert 26 cm, our radius, into meters. The revolutions is also given in revs/min, and we need to convert it into revs/sec so that we can get our final units correct. As a result, we divide the rate by 60 to convert minutes into seconds.

Back to the equation:

v = ((1800*2π)/60) * 0.26

v = (1800*2(3.14)/60) * 0.26

v = (11304/60) * 0.26

v = 188.4 * 0.26

v = 48.984

v = 49 (m/s)

Now that we know the linear velocity, we can find the centripetal acceleration:

a = $\frac{v^{2}}{r}$

a = $\frac{49^{2}}{0.26}$

a = 9234.6 (m/ $s^{2}$ )

Wow! That's fast!

We now have our answers for a and b:

a. 49 (m/s)

b. 9.2 * $10^{3}$ (m/ $s^{2}$ )

If you have any questions on how I got to these answers, just ask!

- breezyツ

5 0

2 years ago

The shortening of a transmitted signal's wavelength and/or an increase in its frequency, which indicates that the object is

Mrrafil [7]

Answer: The Doppler effect occurs when a source of a wave is moving relative to an observer (or the observer is moving relative to the source). In this case, the apparent frequency of the sound, as heard/seen by the observer, is shifted with respect to the original frequency of the wave.

More specifically, the relationship between the apparent frequency, f', and the original frequency, f, is given by:

where:

is the velocity of the wave

is the velocity of the observer relative to the source, and it is positive if the observer is moving towards the source, and negative if the observer is moving away from the source

is the velocity of the source relative to the observer, and it is positive if the source is moving away from the observer, and negative if the source is moving towards the observer

The doppler effect occurs in many daily-life situations: for instance, when an ambulance approaches you, you hear an increase in the apparent frequency of the siren due to the Doppler effect. Another example is the movements of distant galaxies from us: when they move away from us, the apparent frequency of the light they emit decreases, so their wavelengths appear to increase towards the red color (red-shift); on the contrary, when they are moving towards us, the apparent frequency seems to increase, so the wavelength seems to decrease towards the blue color (blue-shift).

Explanation:

7 0

3 years ago

What happens when a mixture is separated

iris [78.8K]

Answer:

the answer would be c

Explanation:

3 0

2 years ago