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4 years ago

An electric device uses 650 watts of power. If the voltage is 120 volts, what is the resistance?

Physics

2 answers:

grigory [225]4 years ago

8 0

Answer: The correct answer is 22.15 ohm.

Explanation:

The expression for the power in terms of resistance and potential is as follows;

$P=\frac{V^{2} }{R}$

Here, V is the potential, P is the power and R is the resistance.

It is given in the problem that an electric device uses 650 watts of power. The voltage of this device is 120 V.

Calculate the resistance of the electric device by rearranging the above expression.

$R=\frac{V^{2} }{P}$

Put V= 120 V and P= 650 W.

$R=\frac{(120)^{2} }{650}$

$R=22.15 ohm$

Therefore, the value of the resistance is 22.15 ohm.

PSYCHO15rus [73]4 years ago

5 0

There are several handy-dandy formulas for electrical power.
Here they are:

-- Power = (voltage) x (current)
-- Power = (current²) x (resistance)
-- Power = (voltage²) x (resistance)

We just have to pick the one that's most convenient.

We know the power and the voltage, and we have to find the resistance.
So we would be smart to use a formula that has power, voltage, and
resistance in it. The last formula on my list is exactly what we want.

-- Power = (voltage²) / (resistance)

   650 w = (120 v)² / (resistance)

   (650 w) x (resistance) = (120 v)²

   resistance = (120 v)² / (650 w) = 22.2 ohms .

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Four students measured the acceleration of gravity. The accepted value for

Ratling [72]

Answer: The student with the largest measurement of percentage error is student 4. Option A is correct.The percent error shows the disparity between the observed value and the actual value. It is given by the expression.

Therefore, we can conclude that the student's measurement that has the largest percent error is student 4.

Explanation:

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2 years ago

A motorcyclist travelling at 30m/s starts to apply his brake when he is 50m from the traffic light that has just turned red .if

Marat540 [252]

Answer:

9m/s²

Explanation:

Given parameters:

Initial velocity = 30m/s

Final velocity = 0m/s

Distance traveled = 50m

Unknown:

Deceleration = ?

Solution:

To solve this problem, we apply the proper motion equation;

V² = U² + 2aS

V is the final velocity

U is the initial velocity

a is the acceleration

S is the distance

Insert the parameters and solve;

0² = 30² + 2(a)50

-900 = 100a

a = -9m/s²

The negative value indicates deceleration.

The motorcycle decelerates at a rate of 9m/s²

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3 years ago

Suppose 1 kg of Hydrogen is converted into Helium. a) What is the mass of the He produced? b) How much energy is released in thi

morpeh [17]

Answer:

a) m = 993 g

b) E = 6.50 × 10¹⁴ J

Explanation:

atomic mass of hydrogen = 1.00794

4 hydrogen atom will make a helium atom = 4 × 1.00794 = 4.03176

we know atomic mass of helium = 4.002602

difference in the atomic mass of helium = 4.03176-4.002602 = 0.029158

fraction of mass lost = $\dfrac{0.029158}{4.03176}$ = 0.00723

loss of mass for 1000 g = 1000 × 0.00723 = 7.23

a) mass of helium produced = 1000-7.23 = 993 g (approx.)

b) energy released in the process

E = m c²

E = 0.00723 × (3× 10⁸)²

E = 6.50 × 10¹⁴ J

4 0

3 years ago

Read 2 more answers

Based on what you have learned about gravity, mass, and distance, write one paragraph to answer the following questions.

natka813 [3]

Bigger objects have more gravitational pull. Bigger, meaning the size and mass. The closer you are to the object, the stronger the pull is. The earth is much bigger, and has a bigger mass than the moon, meaning that the moon is able to orbit around the earth. You are closer to the earth, so you dont randomly get pulled towards thw moon, because earts gravitational pull is stronger than the moons.

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3 years ago

A dumbbell-shaped object is composed by two equal masses, m, connected by a rod of negligible mass and length r. If I1 is the mo

Sati [7]

Answer:

The correct answer to the following question will be Option A (I1 > I2).

Explanation:

Method for moment of inertia because of it's viewpoint including object at a mean distance "r" from the axis is,

⇒ mr²

Let the length of a rod be "r".

The axis passes via the middle of that same rod so that the range from either the axis within each dumbbell becomes " $\frac{r}{2}$ ".

Now,

Now total moment of inertia = sum of inertial moment due to all of the dumbbell

⇒ $l1=m(\frac{r}{2})^2+m(\frac{r}{2})^2$

⇒ $\frac{mr^2}{2}$

Axis moves via one dumbbell because its range from either the axis becomes zero (0) and its impact is zero only at inertia as well as other dumbbell seems to be at a range "r" from either the axis

Now,

Total moment of inertia = moment of inertia of dumbbell at distance "r".

$l2=mr^2$

And now we can infer from this one,

⇒ $mr^2>\frac{mr^2}{2}$

So that "I1 > I2" is the right answer.

5 0

4 years ago