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3 years ago

A motorist driving at 25 meters/second decelerates to

Physics

2 answers:

prisoha [69]3 years ago

6 0

Answer:

Kinetic energy = (1/2) (mass) (speed)²

Before slowing down, the car's speed is 25 m/s,

and its kinetic energy is ...

(1/2) (1,500 kg) (25 m/s)²

= (1/2) (1,500 kg) (625 m²/s²)

= 468,750 joules .

After slowing down, the car's speed is 15 m/s,

(1/2) (1,500 kg) (15 m/s)²

= (1/2) (1,500 kg) (225 m²/s²)

= 168,750 joules.

The car lost (468,750 - 168,750) = 300,000 joules

and you heard it from the KING

timama [110]3 years ago

5 0

Kinetic energy = (1/2) (mass) (speed)²

Before slowing down, the car's speed is 25 m/s,
and its kinetic energy is ...

   (1/2) (1,500 kg) (25 m/s)²

      = (1/2) (1,500 kg) (625 m²/s²)

      =    468,750 joules .

After slowing down, the car's speed is 15 m/s,
and its kinetic energy is ...

   (1/2) (1,500 kg) (15 m/s)²

      = (1/2) (1,500 kg) (225 m²/s²)

      = 168,750 joules.

The car lost (468,750 - 168,750) = 300,000 joules of K.E.

The law of Conservation of Energy says:

That 300,000 joules had to go somewhere.

If it's a standard, gas-powered car, then the kinetic energy got
put into the brakes. The energy turned into heat, and the heat
was carried off in the air.

If it's a more modern electric or hybrid car, then the kinetic energy
spun the wheel motors, turning them temporarily into electrical
generators. The generators converted the kinetic energy into
electrical energy, which got put back into the car's batteries, and
could be used again. That's why electric cars use less gas.

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Is Radioactive decay a way to find the relative age of a rock?<br><br> True<br> False

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To establish the age of a rock or a fossil, researchers use some type of clock to determine the date it was formed. Geologists commonly use radiometric dating methods, based on the natural radioactive decay of certain elements such as potassium and carbon, as reliable clocks to date ancient events.

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3 years ago

a 3000 kg and a 7000 kg Mass attract each other with a force of 0.0015 N. What distance separates the two objects (Radius) (Plea

frutty [35]

Answer:

Explanation:

According to law of gravitation;

F = GMm/d²

G is the universal gravitation

M and m are the masses

d is the distance between the masses

d² = GMm/F

d² = 6.67408 × 10-11 *3000*7000/0.0015

d² = 140.15568*10^-5/0.0015

d² = 1.4016*10^-3/0.0015

d² = 1.4016*10^-3/1.5*10^-3

d² = 0.9344*10

d² = 9.344

d = √9.344

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3 years ago

Sound waves produced by a source pass a point five times every second. Which of the following choices correctly describes the pe

Ugo [173]

The period is 1/5 second, and the frequency is 5 Hz.

Explanation:

Let's start by reviewing some definitions about waves:

- The period of a wave is the time taken for the wave to make one complete cycle. It is indicated with T and it is measured in seconds (s)

- The frequency of a wave is the number of complete cycles made by the wave in one second. It is indicated with f and it is measured in Hertz (Hz). It is equal to the reciprocal of the period:

$f=\frac{1}{T}$

where f is the frequency and T is the period.

In this problem, we have a wave that passes a given point five time per second. This means that the number of oscillations per second is five, and so its frequency is:

$f=\frac{5 cycles}{1 sec}=5 Hz$

It follows than the period of the wave is:

$T=\frac{1}{f}=\frac{1}{5}s$

Therefore, the correct statement is

The period is 1/5 second, and the frequency is 5 Hz.

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3 years ago

1mm is equal to .1 what

bulgar [2K]

Answer:

When you have to do an English-Metric (SI) length conversion, and you already know the English units of length (miles, yards, feet, inches, etc.), all you need to remember is one simple relationship, and you can readily convert any length in the SI system, to the equivalent length in the other.

1 foot (ft) = 0.3048 meters (m)

BIn this case you need your answer in inches. You (hopefully) know there are 12 inches in a foot, so you just do the following:

1 inch (in) = 1/12 ft = 0.3048/12 m = 0.0254 m

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3 years ago

The magnitude of electrical force between a pair of charged particles is ____ as much when the particles are moved half as far a

Gnesinka [82]

The magnitude of the electrical force between a pair of charged particles is 4 Times as much when the particles are moved half as far apart.

This can be easily understood by Columb's law,

$F_{new} = \frac{kQ_{1}Q_{2}}{r^{2}}$

which state's that the amount of electrical force experienced by two charged particles is inversely proportional to the square of the distance between them.

∴ $\frac{F_{new} }{F_{old} } = \frac{Distance_{new}^{2} }{Distance_{old}^{2} }$

Now, we know the new distance is half the original distance,

$F_{new} = \frac{kQ_{1}Q_{2}}{\frac{r}{2}^{2} } \\F_{new} = 4\frac{kQ_{1}Q_{2}}{r^{2}}$

$F_{new} = 4F_{old}$

The electrical force of attraction or electrostatic force of attraction between two charged particles refers to the amount of attractive or repulsive force that exists between the two charges. This can be calculated by Columb's Law.

A charged particle in physics is a particle that has an electric charge. It might be an ion, such as a molecule or atom having an excess or shortage of electrons in comparison to protons. The same charge is thought to be shared by an electron, a proton, or another primary particle.

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1 year ago