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3 years ago

What is the resistance of a bulb of 40w connected in a line of 70v

Physics

1 answer:

olga55 [171]3 years ago

4 0

Answer:

122.5 ohm

Explanation:

Given :

P=40 w

V= 70 V

R=?

Resistance can be calculated as :

$P=\frac{V^{2} }{R} \\40=\frac{(70)^{2} }{R}\\40=\frac{4900}{R} \\R=\frac{4900}{40} \\R=122.5 ohm$

Therefore, resistance of the bulb will be 122.5 ohm

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Space-faring astronauts cannot use standard weight scales (since they are constantly in free fall) so instead they determine the

valentinak56 [21]

Answer:

ma = 48.48kg

Explanation:

To find the mass of the astronaut, you first calculate the mass of the chair by using the information about the period of oscillation of the empty chair and the spring constant. You use the following formula:

$T=2\pi\sqrt{\frac{m_c}{k}}$ (1)

mc: mass of the chair

k: spring constant = 600N/m

T: period of oscillation of the chair = 0.9s

You solve the equation (1) for mc, and then you replace the values of the other parameters:

$m_c=\frac{T^2k}{4\pi^2}=\frac{(0.9s)^2(600N/m)}{4\pi^2}=12.31kg$ (2)

Next, you calculate the mass of the chair and astronaut by using the information about the period of the chair when the astronaut is sitting on the chair:

T': period of chair when the astronaut is sitting = 2.0s

M: mass of the astronaut plus mass of the chair = ?

$T'=2\pi\sqrt{\frac{M}{k}}\\\\M=\frac{T'^2k}{4\pi^2}=\frac{(2.0s)^2(600N/m)}{4\pi^2}\\\\M=60.79kg$ (3)

Finally, the mass of the astronaut is the difference between M and mc (results from (2) and (3)) :

$m_a=M-m_c=60.79kg-12.31kg=48.48kg$

The mass of the astronaut is 48.48 kg

3 0

3 years ago

On Earth, friction can be _____ but not removed.

Whitepunk [10]

Answer:

reduced

Explanation:

The use of bearing surfaces that are themselves sacrificial, such as low shear materials, of which lead/copper journal bearings are an example

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2 years ago

Inez uses hairspray on her hair each morning before going to school. The spray spreads out before reaching her hair partly becau

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The charge on each of the equally charged drops of hairspray willl be 7 × 10 ⁻¹³ C

<h3>What is Columb's law?</h3>

The force of attraction between two charges, according to Coulomb's law, is directly proportional to the product of the charges and inversely proportional to the square of the distance between them.

Similar charges repel each other, whereas charges that are opposed attract each other.

Given data;

Electric force,F = 9 × 10 ⁻⁹ N

Distance between charges,d = 7 × 10⁻⁴ m

Chrge,q₁ = q₂ =q C

From Columb's law;

$\rm F = K \frac{q_1q_2}{d^2} \\\\ 9 \times 10^{-9} = 9 \times 10^9 \frac{q^2}{(7 \times 10^{-4})^2} \\\\ q^2 = 4.9 \times 10^{-25} \\\\ q = 7 \times 10^{-13} \ C$

Hence the charge on each of the equally charged drops of hairspray willl be 7 × 10 ⁻¹³ C

To learn more about Columb's law refer to the link;

brainly.com/question/1616890

#SPJ1

7 0

1 year ago

A racecar driver circles a racetrack with a constant speed of 110 km/hr. Which BEST describes the speed and velocity of the car?

tangare [24]

The answer is B, The speed is constant and the velocity is changing.

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2 years ago

Read 2 more answers

What is the difference between charging by contact and charging by induction in terms of electron transfer.

Veronika [31]

Answer:

the main difference between charging by contact and charging by induction is that in the first case, the two objects are touching, while in the second case, the two objects do not touch

Explanation:

There are three methods of charging an object:

- Charging by friction: this is done by rubbing an object against another object. An example is when a plastic rod is rubbed with a wool cloth. When this is done, electrons are transferred from the wool to the rod, so both objects remain charged at the end of the process

- Charging by contact: this is done by putting in contact a charged object with a neutral, conducting object. In this case, the charges are transferred from the charged object to the neutral object; at the end of the process, the neutral object will also have a net electric charge, so it will be also charged.

- Charging by induction: in this case, we take a charged object, and a neutral object, and we place the two objects close to each other, but without touching. Let's assume that the charged object is negatively charged: in this case, the positive charges in the neutral object are attracted towards the negative charges of the charged object, while the negative charges of the neutral object are repelled away. As a result, the positive and negative charges in the neutral object split apart. If the object is connected to the ground, then negative charges move away, so the neutral object will remain positively charged.

Therefore, the main difference between charging by contact and charging by induction is that in the first case, the two objects are touching, while in the second case, the two objects do not touch.

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3 years ago

What is the resistance of a bulb of 40w connected in a line of 70v​

What is the resistance of a bulb of 40w connected in a line of 70v