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4 years ago

How does the density warm water and Cold water compare

1 answer:

8 0

Cooling a substance causes molecules to slow down and get slightly closer together, occupying a smaller volume that results in an increase in density. Hot water is less dense and will float on room-temperature water. Cold water is more dense and will sink in room-temperature water.

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The practice of playing top hits several times a day on radio stations is called _____. blocking rotation circulation format dri

spin [16.1K]

The practice of playing top hits several times a day on radio stations is called rotation.

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3 years ago

Read 2 more answers

How much tension must a cable withstand to accellerate a 1400 kg car vertically upward at 0.70 m/s^2

MariettaO [177]

Answer:

Below

Explanation:

The cars upward accel adds to the gravity accel (think about how suddenly heavy you feel when the elevator starts to move upward)

F = tension = ma

= 1400 * ( .7 + 9.81) = 14714 N

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2 years ago

Which model of communication was originally described as a one-way process consisting of the following five questions: who, says

tresset_1 [31]

Answer:

Lasswell's 5 step model

Explanation:

This model of communication defines the answers to the questions who says, to whom, says what, the effects it was said with and in what channel.

Lasswell's 5 step model of communication was described as a single way process and was used for the analysis of mass communication, communication in groups and between people to disperse messages into these. It was designed for the purpose of studying and analyzing the business strategies and the media hype of different countries at that time.

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3 years ago

A driver enters a one-lane tunnel at 34.4 m/s. The driver then observes a slow-moving van 154 m ahead travelling (in the same di

navik [9.2K]

Answer:

Ans. B) 22 m/s (the closest to what I have which was 20.16 m/s)

Explanation:

Hi, well, first, we have to find the equations for both, the driver and the van. The first one is moving with constant acceleration (a=-2m/s^2) and the van has no acceletation. Let´s write down both formulas so we can solve this problem.

$X(van)=5.65t+154$

$X(driver)=34.4t+\frac{(-2)t^{2} }{2}$

or by rearanging the drivers equation.

$X(driver)=34.4t+t^{2}$

Now that we have this, let´s equal both equations so we can tell the moment in which both cars crashed.

$X(van)=X(driver)$

$5.65t+154=34.4t-t^{2}$

$0=t^{2} -(34.4-5.65)t+154$ $0=t^{2} -28.75t+154$

To solve this equation we use the following formulas

$t=\frac{-b +\sqrt{b^{2}-4ac } }{2a}$

Where a=1; b=-28.75; c=154

So we get:

$t=\frac{28.75 +\sqrt{(-28.75)^{2}-4(1)(154) } }{2(1)}=21.63s$ $t=\frac{28.75 -\sqrt{(-28.75)^{2}-4(1)(154) } }{2(1)}=7.12s$

At this point, both answers could seem possible, but let´s find the speed of the driver and see if one of them seems ilogic.

$V(driver)=V_{0} +at$ }

$V(driver)=34.4\frac{m}{s} -2\frac{m}{s^{2} } *(7.12s)=20.16\frac{m}{s}$ $V(driver)=34.4\frac{m}{s} -2\frac{m}{s^{2} } *(21.63s)=-8.86\frac{m}{s}$

This means that 21.63s will outcome into a negative speed, for that reason we will not use the value of 21.63s, we use 7.12s and if so, the speed of the driver when he/she hits the van is 20.16m/s, which is closer to answer A).

Best of luck

8 0

3 years ago

Two wheels with fixed hubs, each having a mass of 1kg , start from rest, and forces are applied: F1= 1 N to the first wheel and

irina [24]

Answer:

Explanation:

$m = m_1 = m_2 = 1 kg$