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4 years ago

The velocity ratio of a pulley system is 4. What does it mean? Please answer

Physics

1 answer:

rodikova [14]4 years ago

7 0

Answer:

The force ratio of a machine is 5 and it velocity ratio is 5 means that the load moved is five times the effort applied and the distance moved by the effort is five times the distance moved by the load at the same time interval.

Explanation:

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How many excess electrons must be present on each sphere if the magnitude of the force of repulsion between them is 4.57×10−214.

Musya8 [376]

Answer:

There are 887.5 number of excess electrons on the each spheres.

Explanation:

It is given that, the force of repulsion between two spheres is, $F=4.57\times 10^{-21}\ N$

We know that the force of attraction or repulsion between charges is given by :

$F=\dfrac{kq^2}{r^2}$

It is assumed that the separation between the spheres is 20 cm or 0.2 m. So,

$q=\sqrt{\dfrac{Fr^2}{k}}$

$q=\sqrt{\dfrac{4.57\times 10^{-21}\times (0.2)^2}{9\times 10^9}}$

$q=1.42\times 10^{-16}\ C$

Let there are n excess electrons that must be present on each sphere. It can be given by using quantization of charge as :

$q=ne$

$n=\dfrac{q}{e}$

$n=\dfrac{1.42\times 10^{-16}}{1.6\times 10^{-19}}$

n = 887.5 electrons

So, there are 887.5 number of excess electrons on the each spheres. Hence, this is the required solution.

3 0

3 years ago

Which of these statements best represents the law of conservation of energy

Shkiper50 [21]

Energy cannot be created or destroyed. This statement is known as law of conservation of energy, and it implies that whenever a certain form of energy does change, the loss of this form of energy must have converted into an another type of energy. A typical example is an object falling to the ground: initially, the object has gravitational potential energy. As the object falls down, it loses potential energy (since its altitude from the ground decreases), but it acquires kinetic energy (because its velocity increases). In this example, potential energy has converted into kinetic energy, but the total energy of the object has remained constant.

5 0

3 years ago

The voltage across the terminals of a generator is 5.7 v when it supplies a current of 0.3 A. It becomes 5.1 V when I=0.9A. Find

snow_tiger [21]

Answer:

The emf of the generator is 6V

The internal resistance of the generator is 1 Ω

Explanation:

Given;

terminal voltage, V = 5.7 V, when the current, I = 0.3 A

terminal voltage, V = 5.1 V, when the current, I = 0.9 A

The emf of the generator is calculated as;

E = V + Ir

where;

E is the emf of the generator

r is the internal resistance

First case:

E = 5.7 + 0.3r -------- (1)

Second case:

E = 5.1 + 0.9r -------- (2)

Since the emf E, is constant in both equations, we will have the following;

5.1 + 0.9r = 5.7 + 0.3r

collect similar terms together;

0.9r - 0.3r = 5.7 - 5.1

0.6r = 0.6

r = 0.6/0.6

r = 1 Ω

Now, determine the emf of the generator;

E = V + Ir

E = 5.1 + 0.9x1

E = 5.1 + 0.9

E = 6 V

6 0

3 years ago

A solar cooker, really a concave mirror pointed at the Sun, focuses the Sun's rays 13.8 cm in front of the mirror. Part A What i

shepuryov [24]

From the concept of optics on a curvature of a spherical mirror, the proportion for which the focal length is equivalent to half the radius of curvature is fulfilled. Mathematically this is

$f = \frac{R}{2}$

Here,

f = Focal Length

R = Radius

Rearranging to find the radius we have,

$R = 2f$

Replacing with our values,

R = 2(13.8cm)

R = 27.6cm

Therefore the radius of the spherical surface from which the mirror was made is 27.6cm

6 0

3 years ago

Which of the following statements about the electromagnetic spectrum is true?

Andre45 [30]

Answer:

B. its consist of waves of varying lengtu

6 0

3 years ago