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igomit [66]
4 years ago
6

Can someone please help me with these 2 questions

Physics
1 answer:
jok3333 [9.3K]4 years ago
5 0
1. Answer: 7.75 seconds
Explanation: 76-14=62 metres
62/8=7.75 seconds

2. Answer: 2.5 seconds
Explanation: 28-18=10 metres
10/4=2.5 seconds
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Which graph shows the correct relationship between kinetic energy and speed?
Mamont248 [21]

Answer: D

Explanation:

Kinetic energy = 1/2mV^2

From the formula above, we can deduce that kinetic energy is proportional to the square of speed. That is,

K.E = V^2

Graphically, the relationship isn't linear but a positive exponential. Therefore, option D is the correct answer.

3 0
3 years ago
Katelyn (55 kg) is practicing a drop jump in the biomechanics lab. She steps off a plyometrics box, lands on the force plate, an
suter [353]

Answer:

J = 357.5 kg*m/s

Explanation:

  • The impulse exerted on Katelyn when she was on the force plate, is equal to the change in her momentum, according to Newton's 2nd Law.
  • Assuming as the positive direction the upward direction (coincident with the positive y-axis) we can express the initial momentum as follows:

       p_{o} = m*v_{o} = 55 kg * (-3.0 m/s)  (1)

  • By the same token, the final momentum is as follows:

       p_{f} = m*v_{f} = 55 kg * (3.5 m/s)  (2)

  • As we have already said, the impulse J is just equal to the change in momentum, i.e., the difference between (2) and (1):

      J = p_{f} - p_{o} = m* (v_{f} -v_{o}) = 55 kg* (3.5m/s- (-3.0m/s)) = 357.5 kg*m/s (3)

5 0
3 years ago
Are porkaryotic cells bigger or smaller than eukaryotic cells
Anna11 [10]
The prokaryotic cells are indeed smaller than the eularyotic cells.
Eukaruotic cell size -10-100um
Prokaryotic cell size - 1-10 um
8 0
4 years ago
The threshold of hearing is defined as the minimum discernible intensity of the sound. It is approximately 10−12w/m2. Find the
Monica [59]

Answer:

The distance d from the car at which the sound from the stereo can still be discerned = 97720.5 m

Explanation:

Sound intensity heard at distance is related to the distance with the relation = (power of sound at the source)/(surface area of the wall of an imaginary sphere at the distance in question)

I = P/4πd²

Assuming the car has 2 speakers,

P = 0.06 W × 2 = 0.12 W

d = ?

For the intensity of the least discernible sound,

I = 10⁻¹² W/m²

10⁻¹² = 0.12/4πd²

d = 97720.5 m

8 0
3 years ago
Waves from a radio station have a wavelength of 369 m. They travel by two paths to a home receiver 20.0 km from the transmitter.
Olenka [21]

Answer:

92.25m

Explanation:

In order to solve the exercise, it is necessary to apply the concept of construtive interference due to a path difference.

The formula is given by,

\delta = (m+\frac{1}{2})\frac{\lambda}{n}

where,

n is the index of refraction of the medium in which the wave is traveling

\lambda = wavelenght

\delta = is the path difference

m = integer (0,1,2,3...)

Since in this case we are dealing with an atmospheric environment, where air is predominant, we approximate n to 1.

And since we need the reflected wave,

\delta = 2x

Where x is the distance in one direction without return.

The distance must correspond to the minimum therefore m = 0, so

\delta = (m+\frac{1}{2})\frac{\lambda}{n}

\delta = ({0+\frac{1}{2})\frac{369}{1}

\delta = 184.5m

Then the minimum distance is:

x= \frac{delta}{2}

x = \frac{184.6}{2}

x = 92.25m

Therefore the minimum distance from the mountain to the receiver that produces destructive interference at the receiver is 92.25m

5 0
3 years ago
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