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3 years ago

Calculate the speed of a bike rider who accelerates (from rest) for 5 seconds down a hill at an acceleration of 8

Physics

1 answer:

olya-2409 [2.1K]3 years ago

6 0

Answer:

speed=abs(v)=40ms^-1

Explanation:

acceleration, a = (v-u)/t

since initial velocity u=0 (at rest) and a=8ms^-2,

8=v/5

hence after 5 seconds, v=40ms^-1

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You push on a 30 kg box with a force of 120 N. What is the acceleration of the box2

kumpel [21]

Answer:

Explanation:

120/30=6

8 0

2 years ago

If a nearsighted person has a far point df that is 3.50m from the eye, what is the focal length f1 of the contact lenses that th

olga55 [171]

Answer:

f1= -350cm or -3.5m

f2= 22.1cm or 0.221m

Explanation:

A person is nearsighted when the person's far point is less than infinity. A diverging lens is normally used to correct this eye defect. A diverging lens has a negative focal length as seen in the solution attached.

Farsightedness is when a person's near point is farther than 25cm. This eye defect is corrected using a converging lens. The focal length of a converging lens is positive. This is evident in the solution attached. The near point is also referred to as the least distance of distinct vision.

3 0

3 years ago

Parasaurolophus was a dinosaur whose distinguishing feature was a hollow crest on the head. The 1.5-m-long hollow tube in the cr

Oksi-84 [34.3K]

Answer:

f1 = 58.3Hz, f2 = 175Hz, f3 = 291.6Hz

Explanation:

lets assume speed of sound is 350 m/s.

frequencies of a standing wave modes of an open-close tube of length L

fm = m(v/4L)

where m is 1,3,5,7......

and fm = mf1

where f1 = fundamental frequency

so therefore: f1 = 350 x 4 / 1.5

f1 = 58.3Hz

f2 = 3 x 58.3

f2 = 175Hz

f3 = 5 x 58.3

f3 = 291.6Hz

5 0

3 years ago

Certain materials can become superconductors under what conditions?

tresset_1 [31]

Option (b) is correct. The certain materials can act as superconductors at a very low temperature.

Explanation:

The Superconductivity of a material is the property of the particular substance to provide no resistance to the path of the current through it. The current does not face any hindrance due to the motion of the other particles inside the conductor.

The superconductivity of a substance leads to the flow of current through the substance or the material without any hindrance. The resistance of a substance is due to the motion of the particles inside it. If all the motion occurring inside the substance are seized, there will be no resistance offered by the conductor.

Therefore, the superconductivity can be defined as the state where all the motions inside the a material are seized. This occurs at a very low temperature. The absolute zero temperature $(0\text{ K or }-273^\circ\text{ C})$ is regarded as the temperature where there is no motion in any particle.

Thus, Option (b) is correct. The certain materials can act as superconductors at a very low temperature.

Learn More:

1. An electrical shock happens when electric brainly.com/question/3059888

2. A capacitor with capacitance (c) = 4.50 μf is connected to a 12.0 v battery brainly.com/question/8892837

3. Reason for the difference in resistance of bulb brainly.com/question/10421964

Answer Details:

Grade: High School

Subject: Physics

Chapter: Conductivity

Keywords:

material, superconductor, motion, pressure, cold, temperature, substance, material, conditions, superconductivity.

6 0

3 years ago

Why is a frame of reference important in Physics?

Strike441 [17]

Answer:

A “frame of reference” is a standard relative to which motion and rest may be measured; any set of points or objects that are at rest relative to one another enables us, in principle, to describe the relative motions of bodies.

Explanation:

When you see a ball roll down a street, you can tell the ball is moving because the frame of reference is the streets, whatever may be on the side of the roads, or the Earth. All of these are frames of reference. All measurements of motion will be compared to a frame of reference.

5 0

3 years ago