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3 years ago

Increasing the # of pulleys increases the _ but decreases the amount of applied

Physics

1 answer:

Maksim231197 [3]3 years ago

8 0

Distance, Force

Explanation:

1) Increasing the load will add to the friction on the bearings of the pulleys, thus reducing the efficiency of the system. The ideal mechanical advantage won't change since the ideal mechanical advantage ignores friction.

2) Increasing the number of pulleys will increase the ideal mechanical advantage, but because of friction it will decrease the efficiency. The more pulleys that are turning, the more friction there is, and the less efficient the system will be.

3) Work = force x distance, and what machines do is alter the amount of force you can apply while at the same time reducing the distance moved by the same factor. For instance, a jack multiplies the force you apply by a factor of 100, when you push down on the handle of the jack 100 cm, the car will only go up 1 cm. So the force x distance is the same 100 x force x 1/100 x distance.

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a street light is mounted at the top of a 15 foot pole. A man 6 ft tall walks away from the pole wit a speed of 7 ft/s along a s

Mariulka [41]

Answer:

16.3 ft/s

Explanation:

Let d=distance

and

x = length of shadow.

Therfore,

x=(d + x)

= 6/15

So,

15x = 6x + 6d

9x = 6d.

x = (2/3)d.

As we know that:

dx=dt

= (2/3) (d/dt)

Also,

Given:

d(d)=dt

= 7 ft/s

Thus,

d(d + x)=dt

= (7/3)d (d/dt)

Substitute, d= 7

d(d + x) = 49/3 ft/s.

Hence,

d(d + x) = 16.3 ft/s.

4 0

3 years ago

List two industrial uses for nonmetallic mineral resources

Anni [7]

Answer:

To make useful chemicals and abrasives

Explanation:

4 0

2 years ago

Kyle is flying a helicopter at 125 m/s on a heading of 325 o . If a wind is blowing at 25 m/s toward a direction of 240.0 o , wh

frosja888 [35]

Answer:

The resultant velocity of the helicopter is $\vec v_{H} = \left(89.894\,\frac{m}{s}, -93.348\,\frac{m}{s}\right)$ .

Explanation:

Physically speaking, the resulting velocity of the helicopter ( $\vec v_{H}$ ), measured in meters per second, is equal to the absolute velocity of the wind ( $\vec v_{W}$ ), measured in meters per second, plus the velocity of the helicopter relative to wind ( $\vec v_{H/W}$ ), also call velocity at still air, measured in meters per second. That is:

$\vec v_{H} = \vec v_{W}+\vec v_{H/W}$ (1)

In addition, vectors in rectangular form are defined by the following expression:

$\vec v = \|\vec v\| \cdot (\cos \alpha, \sin \alpha)$ (2)

Where:

$\|\vec v\|$ - Magnitude, measured in meters per second.

$\alpha$ - Direction angle, measured in sexagesimal degrees.

Then, (1) is expanded by applying (2):

$\vec v_{H} = \|\vec v_{W}\| \cdot (\cos \alpha_{W},\sin \alpha_{W}) +\|\vec v_{H/W}\| \cdot (\cos \alpha_{H/W},\sin \alpha_{H/W})$ (3)

$\vec v_{H} = \left(\|\vec v_{W}\|\cdot \cos \alpha_{W}+\|\vec v_{H/W}\|\cdot \cos \alpha_{H/W}, \|\vec v_{W}\|\cdot \sin \alpha_{W}+\|\vec v_{H/W}\|\cdot \sin \alpha_{H/W} \right)$

If we know that $\|\vec v_{W}\| = 25\,\frac{m}{s}$ , $\|\vec v_{H/W}\| = 125\,\frac{m}{s}$ , $\alpha_{W} = 240^{\circ}$ and $\alpha_{H/W} = 325^{\circ}$ , then the resulting velocity of the helicopter is:

$\vec v_{H} = \left(\left(25\,\frac{m}{s} \right)\cdot \cos 240^{\circ}+\left(125\,\frac{m}{s} \right)\cdot \cos 325^{\circ}, \left(25\,\frac{m}{s} \right)\cdot \sin 240^{\circ}+\left(125\,\frac{m}{s} \right)\cdot \sin 325^{\circ}\right)$ $\vec v_{H} = \left(89.894\,\frac{m}{s}, -93.348\,\frac{m}{s}\right)$

The resultant velocity of the helicopter is $\vec v_{H} = \left(89.894\,\frac{m}{s}, -93.348\,\frac{m}{s}\right)$ .

8 0

3 years ago

I Explain why you feel cold when tap or well water in winter. state with reason.

attashe74 [19]

Answer:

We feel cold when tap or well water in winter because heat flows from hot body to cold body.

Explanation:

Our body is in optimal status is a hot body and tap or well water is a cold body. Therefore we feel cold.

3 0

2 years ago

El espectro visible en el aire está comprendido entre la longitud de onda 450 nm del color azul, Determina la velocidad de propa

TiliK225 [7]

Answer:

v = 2,99913 10⁸ m / s

Explanation:

The velocity of propagation of a wave is

v = λ f

in the case of an electromagnetic wave in a vacuum the speed that speed of light

v = c

When the wave reaches a material medium, it is transmitted through a resonant type process, whereby the molecules of the medium vibrate at the same frequency as the wave, as the speed of the wave decreases the only way that they remain the relationship is that the donut length changes in the material medium

λ = λ₀ / n

where n is the index of refraction of the material medium.

Therefore the expression is

v = $\frac{\lambda_o}{n} f$

Let's look for the frequency of blue light in a vacuum

f = $\frac{c }{\lambda_o}$

f = $\frac{3 \ 10^8}{450 \ 10^{-9}}$

f = 6.667 10¹⁴ Hz

the refractive index of air is tabulated

n = 1,00029

let's calculate

v = $\frac{450 \ 10^{-9} }{1.00029} \ 6.667 \ 10^{14}$ 450 10-9 / 1,00029 6,667 1014

v = 2,99913 10⁸ m / s

we can see that the decrease in speed is very small

8 0

2 years ago

Increasing the # of pulleys increases the _______ but decreases the amount of ______ applied

Increasing the # of pulleys increases the _ but decreases the amount of applied