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3 years ago

20-point physics question! :D

2 answers:

Alex3 years ago

8 0

Your hands get warm by a fire because chemical energy is converted into heat energy.

The wood - has chemical energy when you burn it, and then, heat waves rise to the air, which means that we went from :

Chemical energy ⇒ Heat energy

Alright, now, also think about, that energy can never be created not destroyed, so it was obviously transferred, and yet conserved.

If this doesn't make sense, please message me, or comment below. :))

Virty [35]3 years ago

6 0

I think, it must be a chemical. Because the fire is a chemical reaction. So, the chemical energy converted to heat energy.

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Two scientists are discussing their beliefs about something they cannot observe

svetoff [14.1K]

Could it be hypothesis?

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3 years ago

Read 2 more answers

A 20 kg shopping cart moving at a velocity of 0.5 m/s collides with a store wall and

MAXImum [283]

Answer:

Explanation:

The momentum of an object can be found by using the formula

momentum = mass × velocity

From the question we have

momentum = 20 × 0.5

We have the final answer as

Hope this helps you

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2 years ago

Help<br> How much current will flow when a 120 V power supply is connected to a 30<br> resistor ?

AVprozaik [17]

Current= voltage divided by resistance
120/30=4

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2 years ago

g If this combination of resistors were to be replaced by a single resistor with an equivalent resistance, what should that resi

Anettt [7]

<h2>Question:</h2>

In this circuit the resistance R1 is 3Ω, R2 is 7Ω, and R3 is 7Ω. If this combination of resistors were to be replaced by a single resistor with an equivalent resistance, what should that resistance be?

Answer:

9.1Ω

Explanation:

The circuit diagram has been attached to this response.

(i) From the diagram, resistors R1 and R2 are connected in parallel to each other. The reciprocal of their equivalent resistance, say Rₓ, is the sum of the reciprocals of the resistances of each of them. i.e

$\frac{1}{R_X} = \frac{1}{R_1} + \frac{1}{R_2}$

=> $R_{X} = \frac{R_1 * R_2}{R_1 + R_2}$ ------------(i)

From the question;

R1 = 3Ω,

R2 = 7Ω

Substitute these values into equation (i) as follows;

$R_{X} = \frac{3 * 7}{3 + 7}$

$R_{X} = \frac{21}{10}$

$R_{X} = 2.1$ Ω

(ii) Now, since we have found the equivalent resistance (Rₓ) of R1 and R2, this resistance (Rₓ) is in series with the third resistor. i.e Rₓ and R3 are connected in series. This is shown in the second image attached to this response.

Because these resistors are connected in series, they can be replaced by a single resistor with an equivalent resistance R. Where R is the sum of the resistances of the two resistors: Rₓ and R3. i.e

R = Rₓ + R3

Rₓ = 2.1Ω

R3 = 7Ω

=> R = 2.1Ω + 7Ω = 9.1Ω

Therefore, the combination of the resistors R1, R2 and R3 can be replaced with a single resistor with an equivalent resistance of 9.1Ω

4 0

3 years ago

1. A small light bulb is shining light on a basketball (diameter is 23 cm or 9 inches). The light bulb is 3 m from the closest s

siniylev [52]

Answer:

The size (diameter) of the basketball's shadow on the wall is approximately 53.38 cm

Explanation:

The given parameters of the basketball are;

The diameter of the basketball = 23 cm (9 inches)

The distance of the light bulb from the closest side of the basketball = 3 m

The distance from the ball to the wall = 4 m

The distance from the light source to the center of the ball, d = 3 m + 0.23/2 m = 3.115 m

The angle the light ray makes with the edge of the ball, θ = arctan(0.115/3.115)

Therefore, the ratio of the shadow width divided by 2 to the distance from the light from the wall = 0.115/3.115

The distance from the light from the wall = 3 m + 4 m + 0.23 m = 7.23 m

Therefore;

((The width of the shadow)/2)/(The distance from the light from the wall) = 0.115/3.115

∴ ((The width of the shadow)/2)/(7.23 m) = 0.115/3.115

((The width of the shadow)/2) = 7.23 m × 0.115/3.115 = 16629/62300 m ≈ 0.2669 m = 26.69 cm

The width (diameter) of the shadow on the wall = 2 × 16629/62300 m ≈ 0.5338 m = 53.38 cm

The size (diameter) of the basketball's shadow on the wall ≈ 53.38 cm

4 0

2 years ago