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2 years ago

15

Children are told to avoid standing too close to a rapidly moving train because they might get sucked under it. Is this possible

? Explain.

1 answer:

storchak [24]2 years ago

4 0

Answer:

no its not like the undertow in the ocean

Explanation:

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Someone plans to float a small, totally absorbing sphere 0.500 m above an isotropic point source of light,so that the upward rad

mote1985 [20]

Answer:

468449163762.0812 W

Explanation:

m = Mass = $\rhoV$

V = Volume = $\dfrac{4}{3}\pi r^3$

r = Distance of sphere from isotropic point source of light = 0.5 m

R = Radius of sphere = 2 mm

$\rho$ = Density = 19 g/cm³

c = Speed of light = $3\times 10^8\ m/s$

A = Area = $\pi R^2$

I = Intensity = $\dfrac{P}{4\pi r^2}$

g = Acceleration due to gravity = 9.81 m/s²

Force due to radiation is given by

$F=\dfrac{IA}{c}\\\Rightarrow F=\dfrac{\dfrac{P}{4\pi r^2}{\pi R^2}}{c}\\\Rightarrow F=\dfrac{PR^2}{4r^2c}$

According to the question

$F=mg\\\Rightarrow \dfrac{PR^2}{4r^2c}=\rho \dfrac{4}{3}\pi R^3g\\\Rightarrow P=\dfrac{16r^2\rho c\pi Rg}{3}\\\Rightarrow P=\dfrac{16\times 0.002\times 19000\times \pi\times 0.5^2\times 9.81\times 3\times 10^8}{3}\\\Rightarrow P=468449163762.0812\ W$

The power required of the light source is 468449163762.0812 W

4 0

2 years ago

A skydiver finds that she speeds up when she holds her arms close to her body. What does this do?

ArbitrLikvidat [17]

D. Reduces the force of air resistance

7 0

2 years ago

Read 2 more answers

Which type of listening response includes the use of head nods, facial expressions, and short utterances such as "uh-huh" that s

BARSIC [14]

This type of listening response is called back-channel signal. This allows the speaker to know that the listener is attentive or willing to engage a conversation between them. It is shown through short utterances, facial expressions, head nods and others.

4 0

2 years ago

Two resistors of 5.0 and 9.0 ohm are connected in parallel. A 4.0 ohm resistor is then connected in series with the parallel com

rewona [7]

Answer:

I1 = 0.772 A

Explanation:

<u>Given</u>: R1 = 5.0 ohm, R2 = 9.0 ohm, R3 = 4.0 ohm, V = 6.0 Volts

<u>To find</u>: current I = ? A

<u>Solution: </u>

Ohm's law V= I R

⇒ I = V / R

In order to find R (total) we first find R (p) fro parallel combination. so

1 / R (p) = 1 / R1 + 1/ R2 ∴(P) stand for parallel

R (p) = R1R2 / ( R1 + R2)

R (p) = (5.0 × 9.0) / (5.0 + 9.0)

R (p) = 3.214 ohm

Now R (total) = R (p) + R3 (as R3 is connected in series)

R (total) = 3.214 ohm + 4.0 Ohm

R (total) = 7.214 ohm

now I (total) = 7.214 ohm / 6.0 Volts

I (total) = 1.202 A

This the total current supplied by 6 volts battery.

as voltage drop across R (p) = V = R (p) × I (total)

V (p) = 3.214 ohm × 1.202 A = 3.864 volts

Now current through 5 ohms resister is I1 = V (P) / R1

I1 = 3.864 volts / 5 ohm

I1 = 0.772 A

3 0

2 years ago

When a car accelerates from a standing start, the crash test dummy appears to be pressed backward into the seat cushion. Which o

Setler [38]

<u>Answer:</u>

Option: D. Gravity is pulling the crash test dummy in the direction the car is moving.

<u>Explanation: </u>

When a car accelerates from a standing start, the crash test dummy appears to be pressed backward into the seat cushion because the gravity is pulling the crash test dummy in the direction the car is moving.

Basically when the car is starting, the person inside is in static position and the car is going to move. So it is putting a force on the person to move on the same speed. But as the person is sitting static hence gravity is pulling him behind from moving. Hence, The dummy appears to be pressed backward.

7 0

2 years ago