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3 years ago

When an object moves, where does the energy come from?

1 answer:

5 0

Ans: Kinetic and potential energies are found in all objects. If an object is moving, it is said to have kinetic energy (KE). Potential energy (PE) is energy that is "stored" because of the position and/or arrangement of the object. The classic example of potential energy is to pick up a brick.

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An engine causes a car to move 10 meters with a force of 100 N. The engine produces 10,000 J of energy. What is the efficiency o

gregori [183]

Answer:

10%

Explanation:

Efficiency = work done / energy used

e = (10 m × 100 N) / (10,000 J)

e = 0.1

The efficiency is 0.1, or 10%.

4 0

4 years ago

I<br> What are physical properties of matter?

mariarad [96]

Answer:

appearance, texture, color, odor, melting point, boiling point, density, solubility, polarity

Explanation:

7 0

3 years ago

Which factor (s) have the most affect a person’s vital capacity? Rank in order from MOST effect (1) to least effect (5)

jenyasd209 [6]

The factors that affect vital capacity are :

Age
Sex
Height
Body mass
Ethnicity

Explanation:

Vital capacity is the maximum amount of air that a person can exhale once he has filled his lungs with maximum air. So, it is like maximum exhalation after maximum inhalation by a person.

Vital capacity is also equal to Forced Vital Capacity.

Lung usually have their maximum capacity in early adult days and this capacity reduces as the person grows older. So age is the prime factor in this.

A female with same age and height as that of male will have 10-12% less vital capacity than him. So sex is another reason which determines vital capacity.

Person with more height has more vital capacity. This is because lungs capacity is closely related to the third power of person's height.

Person suffering from obesity will have compressed diaphragm, lung and chest cavity , so their vital capacity will be less. So we can say body mass affects vital capacity.

Last factor, ethnicity, is yet to be understood clearly as there is not much evidence of this.

3 0

3 years ago

How will a current change if the voltage in a circuit is held constant while the resistance doubles? 1. it's impossible to predi

laila [671]

According to Ohm's Law:

$I = \frac{V}{R}$

Where: V = Voltage
I = Current
R = Resistance

As you can see here, you can say that Current is directly proportional to Voltage and indirectly proportional to Resistance. This means that as the voltage increases, current increases and as the resistance increases, current decreases.

So in your scenario, if the voltage remains the same, but the resistance is doubled, that means that the current will be halved. So the answer to your question is 2. the current will drop to half of its original value.

4 0

3 years ago

CHEGG 42 mT magnetic field points due west. If a proton of kinetic energy 9 x 10-12 J enters this field in an upward direction,

alexdok [17]

Answer:

The magnitude of the Force is $F = 697 *10^{-15}N$ and the direction is South

Explanation:

From the question we are told that

The magnetic field point due west and since East point toward the positive x -axis $(i)$ then this magnetic field would be mathematically represented as

$\= B = 42(-i)mT = 42*10^{-3} (-i) T$

Now from the question we are told that the kinetic energy is

$KE = 9*10^{-12}J$

Now this kinetic energy can be mathematically represented as

$KE = \frac{1}{2}mv^2$

Where m is the mass of proton which has a general value of

$m = 1.67*10^{-27}kg$

Now making the subject of the formula

$v = \sqrt{\frac{KE}{0.5 * m} }$

Substituting values we have

$v = \sqrt{\frac{9*10^{-12}}{0.5 * 1.67*10^{-27}} }$

$= 10.37*10^7m/s$

Now from the question we are told that proton is moving upward which is in the positive z direction so the velocity of the proton would be in the positive

So the velocity would be

$\= v = 10.37*10^{7} \r k \ m/s$