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nataly862011 [7]
3 years ago
13

A 0.25 kg steel ball is tied to the end of a string and then whirled in a vertical circle at a constant speed v. The length of t

he string is 0.62 m, and the tension in the string when the ball is at the top of the circle is 4.0 N. What is v
Physics
1 answer:
TiliK225 [7]3 years ago
7 0

Answer:

Explanation:

Let the tension in the string be T . At the top of the circle , total force acting on them = T + mg . This will provide centripetal force

T + mg = m v² / r

4 + .25 x 9.8 = .25 x v² / .62

6.45 = .25 v² / .62

v² = 16

v = 4 m /s .

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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} = 2.1Ω

(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
An electric heater rated 500 W operates 24 hours/ day. what is the cost of energy to operate it for 20 days at Rs. 2.00 per kWh
Rina8888 [55]

Answer:

Rs. 480.00

Explanation:

1kW = 1000W

therefore 500W = 0.5kW

20 × 24hrs = 480hrs in total.

0.5kW × 480hrs = 240kWh

if rs. 2 for 1kWh

then, 240kWh × 2 = Rs. 480.

4 0
1 year ago
Read 2 more answers
A scientist reports a measurement of the temperature of the surface of a newly discovered planet as negative 20 Kelvin. What con
jarptica [38.1K]

Answer:

The temperature of this newly discovered planet violates the third law of thermodynamic, there is a mistake in this value.

Explanation:

The third law of the Thermodynamic says:

<u> At zero kelvin all molecular movement stops, which means that the entropy will be zero at this temperature.</u>

So we can say there is no thermodynamic system that has temperature values less than 0 K.

The conclusion of the report will be.

The temperature of this new planet violates the third law of thermodynamic, there is a mistake in this value.

I hope it helps you!

3 0
2 years ago
What do we mean by the event horizon of a black hole?
Fynjy0 [20]

The correct answer is: C. It is the point beyond which neither light nor anything else can escape.

6 0
3 years ago
Explain why dissolving is a physical change
zloy xaker [14]
Because the kinetic energy start to decrease, for example if we put sugar in a high temperature tea and we shake it what will happen to the sugar will the kinetic energy increase or decrease, it will probably decrease, just like us the people when we enter a cold room and we have a hot temp.
8 0
3 years ago
Read 2 more answers
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