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mixer [17]
3 years ago
12

during a workout, a football player pushes a blocking dummy a distance of 30 m. while pushing the dummy the same distance a seco

nd time, what would the player need to change to be certain that power output increases? the player would need to use a greater force and take more time. the player would need to use a greater force and take less time. the player would need to use a smaller force and take more time. the player would need to use a smaller force and take less time.
Physics
2 answers:
babymother [125]3 years ago
8 0
Power=\frac{Work}{Time}=\frac{Force\times distance}{time}

If he wants to increase power, force must increase and decrease time.
Dmitrij [34]3 years ago
5 0

B.........................

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A lever is being used to move a heavy stone from a garden. The stone weighs 250 newtons. The board used as a lever is 6 meters l
DerKrebs [107]

Answer:

Force = 125 [N]

Explanation:

In the attached image we can see a sketch of the lever system.

And if we make a sum of moments at the point O equal to zero (0).

In the equation showed in the image, we can determinate the force that we need

7 0
3 years ago
A plane travels 350 km south along a straight path with an average velocity of 125 km/h to the south. The plane has a 30 minute
faust18 [17]
Average Velocity = Total Displacement / Total time

1st part of journey,  350 km at velocity 125 km/h

Time = 350 / 125 = 2.8 hours.

2nd part of journey,  220 km at velocity 115 km/h

Time = 220 / 115 = 1.9 hours


Average Velocity = Total Displacement / Total time

                               = (350 + 220) / (2.8 + 1.9)

                                =   570 / 4.7  ≈ 121.3 km/hr

Average Velocity ≈ 121 km/hr due south. 

Option C. 
6 0
3 years ago
The electric-power industry is interested in finding a way to store electric energy during times of low demand for use during pe
Stolb23 [73]

Answer: True

Explanation: Inductors are similar to resistors, due to the fact that they offer resistance to current flow, but Inductors are different from resistors in that, while resistors loss electric energy in a circuit in the form of heat, an inductor stores that energy in the form of a magnetic field.

As current passes through an inductor overtime it tends to store current in the form of magnetic field. Therefore the electric-power industry can store energy in large Inductors.

5 0
3 years ago
A small airplane takes on 302 l of fuel. If the density of the fuel is 0.821 g/ml, what mass of fuel has the airplane taken on?
ella [17]

To calculate the mass of the fuel, we use the formula

m = V \times  \rho

Here, m is the mass of fuel, V is the volume of the fuel and its value is V =302 \ L =  302 \ L \times \frac{10^{3}m L }{L} = 302 \times 10^{3} \ mL and  \rho is the density and its value of  0.821 g/mL.

Substituting these values in above relation, we get  

m = 302 \times 10^{3} \ mL \times 0.821 g/mL = 247942 g \\\\ m = 247. 94 \ kg

Thus, the mass of the fuel 247 .94 kg.

8 0
3 years ago
The wavelength of red helium-neon laser light in air is 632.8 nm.(a) What is its frequency? Hz(b) What is its wavelength in glas
vekshin1
<h2>Answers:</h2>

The speed of a wave is given by:

v=f.\lambda  (1)

Where f is the frequency and  \lambda the wavelength.

In the case of light, its speed is:

c=f.\lambda (2)

On the other hand, the described situation is known as Refraction,   a phenomenon in which the light changes its direction when passing through a medium with a refractive index different from the other medium.  

In this context, the Refractive index n is a number that describes how fast light propagates through a medium or material, and is defined as the relation between the speed of light in vacuum (c=3(10)^{8}m/s) and the speed of light v in the second medium:

n=\frac{c}{v} (3)

In addition, as the light changes its direction, its wavelength changes as well:

n=\frac{\lambda_{air}}{\lambda_{glass}} (4)

Knowing this, let's begin with the answers:

<h2>a) Frequency</h2>

From equation (2) we can find f:

f=\frac{c}{\lambda}  (5)

Knowing that 1nm=(10)^{-9}m:

f=\frac{3(10)^{8}m/s}{632.8(10)^{-9}m}  

f=4.74(10)^{14}Hz}     (6)   >>>Frequency of the helium-neon laser light

<h2>b) Wavelength in glass</h2>

We already know the wavelength of the light in air \lambda_{air} and the index of refraction of the glass.

So, we only have to find the wavelength in glass \lambda_{glass} from equation (4):

\lambda_{glass}=\frac{\lambda_{air}}{n}

\lambda_{glass}=\frac{632.8(10)^{-9}m}{1.48}

\lambda_{glass}=427(10)^{-9}m=427nm   (7)   >>>Wavelength of the helium-neon laser light in glass

<h2>c) Speed in glass</h2>

From equation (3) we can find the speed vof this light in glass:

v=\frac{c}{n}

v=\frac{3(10)^{8}m/s}{1.48}

v=2.027(10)^{8}m/s   (8)  >>>Speed of the helium-neon laser light in glass

7 0
3 years ago
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