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3 years ago

Which of the following scenarios describes an object being acted on by a conservative force?

Physics

1 answer:

andrew11 [14]3 years ago

7 0

Answer:

Option: A feather falls from one end of a tube to the other inside a vacuum.

Explanation:

To answer the question we need to first understand what is meant by Conservative Force.

In principle, Conservative forces are basically forces that are not affected by outside parameters (such as friction, air resistance etc). If the present force is strictly based on the initial and the final location of the object, with the inbetween path being irrelevant, the force will be conservative. A conservative force will be zero if we are looking at a closed path-system. We can also say that the system's energy loss will not be a function of the distance covered but is a function of displacement.

Looking at the available options, we can see that:

Option A: A woman hikes up a mountain to a point 20 feet above ground.

This is a Non Conservative force as this case does not depend just on displacement but also in the path in between, i.e. hiking up the mountain there will be other forces that will affect the woman such as air resistance.

Option B: A dishwasher was pulled up to a window by a rope, using a pulley system.

This is a Non Conservative force as this case does not depend just on displacement but also in the inbetween path along with the forces present in a pulley system such as friction.

Option C: A feather falls from one end of a tube to the other inside a vacuum.

This is a Conservative force as here we are looking at a vacuum and its a closed system of no other forces present due to vacuum. However, we CAN'T say that ALL forces in a Vacuum Are Conservative because there are cases of dynamic steady state fields where the system is prone to other forces (i.e. open system).

Option D: A puck glides across and slowly comes to a stop on an ice rink.

This is a Non Conservative force as this case does not depend just on displacement but also the motion until it comes to a stop, which is possibly due to the friction between the ice rink and the puck.

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3 years ago

20. Which statement is false? Rewrite it so that it is true. a. Fusion involves the combination of two smaller atoms into a larg

Annette [7]

Answer:

c. Fission and fusion are two processes that release very little amounts of energy.

Explanation:

This statement is false. In fact, both fission and fusion are processes which release very large amounts of energy. The statement can be rewritten as it is true as follows:

"Fission and fusion are two processes that release very large amounts of energy."

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$E = \Delta m c^2$

where

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3 years ago

Light is incident perpendicularly on four transparent films of different thickness. The thickness of each film is given in the d

exis [7]

Answer:

1/4 λ film

Explanation:

Let L = total path length then L = 2 t where t is film thickness

There will be a 180 deg phase change at the air-film interface but no

phase change at the film-air interface

L = n * wavelength / 2 where n = 1, 3, 5, 7 etc

(the total path L must be an odd number of 1/2 wavelengths)

Or t = n * wavelength / 4 (the film must be an odd number

of 1/4 wavelengths thick)

1/4 λ film satisfies this condition

Note: Find the missing diagram in the attachment section.

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3 years ago

A 2.0 kg mass moving at 5.0 m/s suddenly collides head-on with a 3.0 kg mass at rest. If the collision is perfectly inelastic, h

liberstina [14]

Answer:

correct answer is (c) 15 J

Explanation:

given data

mass m1 = 2 kg

velocity V1 = 5 m/s

mass other = 3 kg

so mass m2 = 2+ 3 kg = 5 kg

solution

we will apply here conservation of momentum:

m1V1 = m2V2 ..........................1

put here value and we get velocity v2

(2.0) × (5.0) = (2.0 + 3.0) × V

solve it we get

10 = 5 × V 2

V2 = 2.0 m/s

so here kinetic energy will be

KE = ½ × m × v²

∆KE = ½ × m1 × (v1)² - ½ × m2 × (v2) ²

∆KE = 0.5 × 2 × 25 - 0.5 × 5 × 4

∆KE = 25 - 10

∆KE = 15 J

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2 years ago

A car travels 300 km in the first 3 hours of a trip. Then it hits traffic and travels only 60 km during the last hour. What is t

Nadusha1986 [10]

Question

A car travels 300 km in the first 3 hours of a trip. Then it hits traffic and travels only 60 km during the last hour. What is the average speed of the of the car?

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C.) 90 Km/h is your answer

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3 years ago