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3 years ago

This problem has been solved!

Physics

1 answer:

irakobra [83]3 years ago

5 0

Answer:

The correct answer is option '5': The type of metal from which the plate is made.

Explanation:

According to the principle of photoelectric effect we know that electron's are only emitted from a surface of metal if the frequency of the light is larger than a threshold frequency that depends on the metal and is known as threshold function of the metal. The ejection of the electrons is independent of intensity of the incident light meaning any light of frequency lower than work function will not eject electrons from the metal no matter whatever the intensity of the light, or the surface area or thermal conductivity, time of illumination.

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A 50N girl pushes a 10,000 N car with force of 200N. What is the force the car pushes back at the girl? *

miss Akunina [59]

Answer:

200N

Explanation:

EVERY FORCE IS OPPOSED BY AN EQUAL FORCE, REGARDLESS OF THE WEIGHT OF THE OBJECTS APPLYING THE FORCE.

8 0

3 years ago

A 0.400-kg object is swung in a circular path and in a vertical plane on a 0.500-m-length string. If the angular speed at the bo

Talja [164]

Answer:

T = 16.72 N

Explanation:

When the object is swung in a circular path, and in a vertical plane, there are two forces external to the object acting on it at any time: the gravity (which is always downward) and the tension in the string (which always points towards the center of the circle).

At the bottom of the circle, the tension is directly upward, so these two forces, are opposite each other, and the difference between them is the centripetal force , which at this point, keeps the object swinging in a circle.

This is the point of the trajectory where T is maximum.

We can apply Newton's 2nd Law, choosing an axis vertical (y-axis) being the upward direction the positive one, as follows:

T- m*g = m*a

The acceleration, at the bottom of the circle, is only normal (as there are no forces in the horizontal direction) , and is equal to the centripetal acceleration, as follows:

ac = v² / r = ω²*r⇒ T- m*g = m*ω²*r

Replacing by the givens, we can solve for T as follows:

T = m* (ω²*r+g) = 0.4 kg*((8.00)² rad/sec²*0.5m)+9.8 m/s²) = 16.72 N

5 0

3 years ago

A ballast is dropped from a stationary hot-air balloon that is at an altitude of 576 ft. Find (a) an expression for the altitude

Nadya [2.5K]

Answer:

Explanation:

If a ball dropped from a stationary hot-air balloon that is at an altitude of 576 ft, an expression for the altitude of the ballast after t seconds can be expressed using the equation of motion;

$S = ut + \frac{1}{2}at^{2}$

S is the altitude of the ballest

u is the initial velocity

a is the acceleration of the body

t is the time taken to strike the ground

Since the body is dropped from a stationary air balloon, the initial velocity u will be zero i.e u = 0m/s

Also, since the ballast is dropped from a stationary hot-air balloon, the body is under the influence of gravity, the acceleration will become acceleration due to gravity i.e a = +g

Substituting this values into the equation of the motion;

$S = 0 + \frac{1}{2}gt^2\\ S = \frac{1}{2}gt^2\\$

a) An expression for the altitude of the ballast after t seconds is therefore

$S = \frac{1}{2}gt^2\\$

b) Given S = 576ft and g = 32ft/s², substituting this into the formula in (a);

$576 = \frac{1}{2}(32)t^2\\\\\\576*2 = 32t^2\\1152 = 32t^2\\t^2 = \frac{1152}{32} \\t^2 = 36\\t = \sqrt{36}\\ t = 6.0secs$

This means that the ballast strikes the ground after 6secs

c) To get the velocity when it strikes the ground, we will use the equation of motion v = u + gt.

v = 0 + 32(6)

v = 192ft

7 0

4 years ago

What would happen if you try to put two balloons with the same charge together

ivanzaharov [21]

Answer:

they would repel because they have the same charge. Charges that are different will stick together.

3 0

3 years ago

Read 2 more answers

We often refer to the electricity at a typical household outlet as being 120 V. In fact, the voltage of this AC source varies; t

astra-53 [7]

Explanation:

We often refer to the electricity at a typical household outlet as being 120 V. In fact, the voltage of this AC source varies; the 120 V is "the rms value of the voltage".

The rms value of voltage is given by :

$V_{rms}=\dfrac{V_{pk}}{\sqrt{2}}$

Where

$v_{pk}$ is the peak value of voltage

So, the correct option is (d). " rms value of voltage".

3 0

4 years ago