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2 years ago

I really need help, whats 2+2

Physics

1 answer:

nevsk [136]2 years ago

7 0

Answer:

2+2 =4

Explanation:

i counted my fingers ✌✌

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Please answer the question in the picture, worth 25 points

viktelen [127]

Answer:

Option C, increases and decreases

Explanation:

When an object making noise approaches you, the wave frequency increases leading to a higher pitch. Conversely, when it moves away from you or retreats, the wave frequency decreases leading to a lower pitch. This can be observed in ambulance sirens.

5 0

2 years ago

A fireman of 80 kg slides down a pole.When he reaches the bottom, 4.2 m below his starting point, his speed is 2.2 m/s . By how

levacccp [35]

Answer:

3099 J

Explanation:

The increase in thermal energy corresponds to the mechanical energy lost in the process.

The mechanical energy is given by the sum of gravitational potential energy and kinetic energy of the fireman:

$E=K+U$

At the top of the pole, the fireman has no kinetic energy, so all his mechanical energy is just potential energy:

$E=U=mgh=(80 kg)(9.8 m/s^2)(4.2 m)=3293 J$

When the fireman reaches the bottom, he has no gravitational potential energy, so his mechanical energy is just given by his kinetic energy:

$E=K=\frac{1}{2}mv^2=\frac{1}{2}(80 kg)(2.2 m/s)^2=194 J$

So, the loss in mechanical energy was

$\Delta E=3293 J-194 J=3099 J$

and this corresponds to the increase in thermal energy.

7 0

3 years ago

which statements about acceleration are true? check all that apply. a. the si units of acceleration are m/s2. b. for acceleratio

tatiyna

The first thing you should know is that acceleration is a vector, therefore, it has magnitude, and direction.

By definition, we have that the vector acceleration is given by:

$a = \frac{dv}{dt}\\$

Where,

dv/dt: derived from the velocity vector with respect to time,

Therefore, the units of the vector acceleration are:

$a = \frac{\frac{m}{s}}{s}\\$

$a = \frac{m}{s^2}$

The symbol of acceleration is:

$a^{->}$

Answer:

The statements about acceleration that are true are:

a. the si units of acceleration are m/s2.

b. for acceleration, you must have a number, a unit, and a direction.

d. the symbol for acceleration is (True, only if the symbol is the same as above)

5 0

3 years ago

Read 2 more answers

High-voltage power lines are a familiar sight throughout the country. The aluminum wire used for some of these lines has a cross

goblinko [34]

Answer:

Explanation:

For resistance of a wire , the formula is as follows

R = ρ L / S

where ρ is specific resistance , L is length and S is cross sectional area

Given L = 14 000 m ,

S = 4.8 x 10⁻⁴ m²

specific resistance of aluminum = 2.8 x 10⁻⁸ ohm-meter

Putting the values in the formula

R = 2.8 x 10⁻⁸ x 14 x 10³ / (4.8 x 10⁻⁴ )

R = 0.8167 ohm .

= .82 ohm .

5 0

2 years ago

If the primary source of atmospheric thermal energy on Earth is energy from the Sun, what conclusion can be made from the diagra

Tamiku [17]

Answer:B

Explanation:

Because the Earth's core isn't moving around earth therefore the center of Earth will forever be warm

4 0

3 years ago