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2 years ago

He graph below shows the velocity f(t) of a runner during a certain time interval:

Physics

2 answers:

Annette [7]2 years ago

5 0

The following that describes the intercepts on the graph is "The initial velocity of the runner was 4 m/s, and the runner stopped after 8 seconds." It is because the starting point of the line is at 4 and then the ending point is at 8.

iragen [17]2 years ago

4 0

Answer is "the initial velocity of the runner was 4 m/s, and the runner stopped after 8 seconds".

This is a velocity - time graph.

At t = 0 s, the graph has a velocity as 4 m/s. This means, the runner has an initial velocity as 4 m/s.

At t = 4 s, the runner has reached his maximum velocity as 8 m/s and acceleration is 1 m/s².

After t = 4 s, the velocity has decreased with the time means it is a negative acceleration. 

At t = 8 s, the velocity of the runner has reached to zero means runner has stopped after 8 seconds.

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explain why the impact of one heavy stone would produce waves with higher amplitude than the impact of the light stone would

DerKrebs [107]

The heavy stone would produce waves with a higher amplitude, rather than the smaller stone, because since the stone is heaver its going to have a grater impact and displace more water to create a bigger wave.

5 0

2 years ago

A heat engine accepts 200,000 Btu of heat from a source at 1500 R and rejects 100,000 Btu of heat to a sink at 600 R. Calculate

diamong [38]

To solve the problem it is necessary to apply the concepts related to the conservation of energy through the heat transferred and the work done, as well as through the calculation of entropy due to heat and temperatra.

By definition we know that the change in entropy is given by

$\Delta S = \frac{Q}{T}$

Where,

Q = Heat transfer

T = Temperature

On the other hand we know that by conserving energy the work done in a system is equal to the change in heat transferred, that is

$W = Q_{source}-Q_{sink}$

According to the data given we have to,

$Q_{source} = 200000Btu$

$T_{source} = 1500R$

$Q_{sink} = 100000Btu$

$T_{sink} = 600R$

PART A) The total change in entropy, would be given by the changes that exist in the source and sink, that is

$\Delta S_{sink} = \frac{Q_{sink}}{T_{sink}}$

$\Delta S_{sink} = \frac{100000}{600}$

$\Delta S_{sink} = 166.67Btu/R$

On the other hand,

$\Delta S_{source} = \frac{Q_{source}}{T_{source}}$

$\Delta S_{source} = \frac{-200000}{1500}$

$\Delta S_{source} = -133.33Btu/R$

The total change of entropy would be,

$S = \Delta S_{source}+\Delta S_{sink}$

$S = -133.33+166.67$

$S = 33.34Btu/R$

Since $S\neq 0$ the heat engine is not reversible.

PART B)

Work done by heat engine is given by

$W=Q_{source}-Q_{sink}$

$W = 200000-100000$

$W = 100000 Btu$

Therefore the work in the system is 100000Btu

4 0

2 years ago

According to Dr. paul Narguizian professor of Biology and Science Education at California State University, ______ are generaliz

Mazyrski [523]

Answer:

I believe the correct answer would be A :)

Explanation:

3 0

1 year ago

A ship 1200m off shore fires a gun. how long after the gun is fired will it be heard on the shore?

ryzh [129]

Answer:

We know that the speed of sound is 343 m/s in air

we are also given the distance of the boat from the shore

From the provided data, we can easily find the time taken by the sound to reach the shore using the second equation of motion

s = ut + 1/2 at²

since the acceleration of sound is 0:

s = ut + 1/2 (0)t²

s = ut (here, u is the speed of sound , s is the distance travelled and t is the time taken)

Replacing the variables in the equation with the values we know

1200 = 343 * t

t = 1200 / 343

t = 3.5 seconds (approx)

Therefore, the sound of the gun will be heard at the shore, 3.5 seconds after being fired

6 0

2 years ago

Which of the following statements is/are true? Check all that apply. Check all that apply. Power is the rate at which energy is

AlladinOne [14]

Answer:

True statements:

Power is the rate at which work is done.

Power is the rate at which energy is transformed.

The SI unit of power is watt.

A person is limited in the total work he or she can do by the rate at which energy can be transformed.

Explanation:

The above statements are true.

1. Power is defined as the rate at which work is done.

2. Power is the rate at which energy is transformed. Whenever energy changes its form, or moves from one place to another, the rate at which it makes those changes is described as power.

3. The SI Unit of power is watts. If 1 joule of energy is converted by an object in 1 second then its power is called one watt.

So, the statement 'the SI unit of power is the horsepower' is false.

4. A person is limited in the total work he or she can do by the rate at which energy can be transformed i.e, his power. He is not only limited by the total energy required.

So, the statement 'A person is limited in the total work he or she can do only by the total energy required' is not completely true.

5 0

2 years ago