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3 years ago

A stone is dropped from a cliff at time t = 0 and strikes the ground below.

Physics

1 answer:

Dafna1 [17]3 years ago

5 0

Answer:

........(1)

And that of the other stone is

S=u(t−n)+

[g(t−n)

]........(2)

Since both the stones meet at the distance so equation (1)and equation(2) will be equal

=u(t−n)+

[g(t−n)

]

=2ut−2un+gt

+gn

−2gnt

t(2gn−2u)=gn

−2un

(gn−u)

−u)

now putting value of t in equation(1)

⎣

⎢

⎡

gn−u

[n(

−u)]

⎦

⎥

⎤

⎣

⎢

⎡

(gn−u)

−u)

⎦

⎥

⎤

Explanation:

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Explain how you can recognize the sound of a flute

lions [1.4K]

Answer:

It's airy, light, poetic, mellow, bright, wafting, ethereal, rich, soft, graceful, penetrating, brilliant, clear, shrill, silvery, wind-like, whistling, whispering, humming, filigree, sighing, aspirate.

5 0

3 years ago

Read 2 more answers

A bungee jumper of mass 75kg is attached to a bungee cord of length L=35m. She walks oﬀ a platform (with no initial speed), reac

attashe74 [19]

Answer:

1. 77.31 N/m

2. 26.2 m/s

3. increase

Explanation:

1. According to the law of energy conservation, when she jumps from the bridge to the point of maximum stretch, her potential energy would be converted to elastics energy. Her kinetic energy at both of those points are 0 as speed at those points are 0.

Let g = 9.8 m/s2. And the point where the bungee ropes are stretched to maximum be ground 0 for potential energy. We have the following energy conservation equation

$E_P = E_E$

$mgh = kx^2/2$

where m = 75 kg is the mass of the jumper, h = 72 m is the vertical height from the jumping point to the lowest point, k (N/m) is the spring constant and x = 72 - 35 = 37 m is the length that the cord is stretched

$75*9.8*72 = 37^2k/2$

$k = (75*9.8*72*2)/37^2 = 77.31 N/m$

2. At 35 m below the platform, the cord isn't stretched, so there isn't any elastics energy, only potential energy converted to kinetics energy. This time let's use the 35m point as ground 0 for potential energy

$mv^2/2 = mgH$

where H = 35m this time due to the height difference between the jumping point and the point 35m below the platform

$v^2/2 = gH$

$v = \sqrt{2gH} = \sqrt{2*9.8*35} = 26.2 m/s$

3. If she jumps from her platform with a velocity, then her starting kinetic energy is no longer 0. The energy conservation equation would then be

$E_P + E_k = E_E$

So the elastics energy would increase, which would lengthen the maximum displacement of the cord

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4 years ago

For the PE formula, why is the height required for calculations? Why do we need to know the height in order to determine PE? *

Fudgin [204]

Answer:

Answer in Explanation

Explanation:

Whenever we talk about the gravitational potential energy, it means the energy stored in a body due to its position in the gravitational field. Now, we know that in the gravitational field the work is only done when the body moves vertically. If the body moves horizontally on the same surface in the Earth's Gravitational Field, then the work done on the body is considered to be zero. Hence, the work done or the energy stored in the object while in the gravitational field is only possible if it moves vertically. This vertical distance is referred to as height. <u>This is the main reason why we require height in the P.E formula and calculations.</u>

The derivation of this formula is as follows:

Work = Force * Displacement

For gravitational potential energy:

Work = P.E

Force = Weight = mg

Displacement = Vertical Displacement = Height = h

Therefore,

P.E = mgh

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3 years ago

A object is 200 miles from the center of a circle and makes a circuit every 2 hours. How fast is it moving?

Tanya [424]

Answer: 628.31 miles/h

Explanation:

The equation to calculate the average speed $s$ of an object moving in a circular path is:

$s=\frac{2 \pi r}{T}$ (1)

Where:

$r=200 miles$ is the radius of the circumference

$T=\frac{1}{f}$ is the period, which has an inverse relation with the frequency $f=\frac{1 circuit}{2 h}=0.5 h^{-1}$ . Then $T=\frac{1}{0.5 h^{-1}}=2 h$