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Brut [27]
3 years ago
5

A bungee cord can stretch, but it is never compressed. When the distance between the two ends of the cord is less than its unstr

etched length L0, the cord folds and its tension is zero. A particular bungee cord has an unstretched length of L0 = 32 m; when it is stretched to L > L0, the cords tension obeys Hooke’s law with "spring" constant 50 N/m. To test the cords reliability, one end is tied to a high bridge of height 91 m (above the surface of a river) and the other end is tied to a steel ball of mass 93 kg, which is dropped off the bridge. The ball stops in the air a few meters before it hits the water — then the cord pulls it back up. Find the ball’s height above the water’s surface at this lowest point of its trajectory. The acceleration of gravity is 9.8 m/s 2 . For simplicity, neglect the cord’s own weight and inertia as well as any air drag on the ball and the cord. Answer in units of m.
Physics
1 answer:
Ksju [112]3 years ago
3 0

Answer:

Explanation:

Given that

g=9.8m/s²

The spring constant is

k=50N/m

The length of the bungee cord is

Lo=32m

Height of bridge which one end of the bungee is tied is 91m

A steel ball of mass 92kg is attached to the other end of the bungee.

The potential energy(Us) of the steel ball before dropped from the bridge is given as

P.E= mgh

P.E= 92×9.8×91

P.E= 82045.6 J

Us= 82045.6 J

Potential energy)(Uc) of the cord is given as

Uc= ½ke²

Where 'e' is the extension

Then the extension is final height extended by cord minus height of cord

e=hf - hi

e=hf - 32

Uc= ½×50×(hf-32)²

Uc=25(hf-32)²

Using conservation of energy,

Then,

The potential energy of free fall equals the potential energy in string

Uc=Us

25(hf-32)²=82045.6

(hf-32)² = 82045.6/25

(hf-32)²=3281.825

Take square root of both sides

√(hf-32)²=√(3281.825)

hf-32=57.29

hf=57.29+32

hf=89.29m

We neglect the negative sign of the root because the string cannot compressed

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A 545-kg satellite is in a circular orbit about Earth at a height above Earth equal to Earth's mean radius. (a) Find the satelli
Art [367]

Answer

given,

mass of satellite = 545 Kg

R = 6.4 x 10⁶ m

H = 2 x 6.4 x 10⁶ m

Mass of earth = 5.972 x 10²⁴ Kg

height above earth is equal to earth's mean radius

a) satellite's orbital velocity

   centripetal force acting on satellite = \dfrac{mv^2}{r}

     gravitational force = \dfrac{GMm}{r^2}

    equating both the above equation

    \dfrac{mv^2}{r} = \dfrac{GMm}{r^2}

      v = \sqrt{\dfrac{GM}{r}}

      v = \sqrt{\dfrac{6.67 \times 10^{-11}\times 5.972 \times 10^{24}}{2 \times 6.4 \times 10^6}}

          v = 5578.5 m/s

b) T= \dfrac{2\pi\ r}{v}

   T= \dfrac{2\pi\times 2\times 6.4 \times 10^6}{5578.5}

   T= \dfrac{2\pi\times 2\times 6.4 \times 10^6}{5578.5}

          T = 14416.92 s

          T = \dfrac{14416.92}{3600}\ hr

          T = 4 hr

c) gravitational force acting

  F = \dfrac{GMm}{r^2}

  F = \dfrac{6.67 \times 10^{-11}\times 545 \times 5.972 \times 10^{24} }{(6.46 \times 10^6)^2}

     F = 5202 N

4 0
3 years ago
What is the value of the equivalent resistance for the three resistors connected in series?
Harman [31]

The value of the equivalent resistance for the three resistors connected in series will be the sum of the three values.

To find the answer, we have to know more about the equivalent resistance.

<h3>What is meant by equivalent resistance?</h3>
  • equivalent resistance is the total value of the resistance connected in a circuit.
  • If n resistors are connected in series, then the equivalent resistance will be,

                R_E=R_1+R_2+..........+R_n

  • In our question we have three resistors. Thus, the equivalent resistance will be,

               R_E=R_1+R_2+R_3

Thus, we can conclude that, the value of the equivalent resistance for the three resistors connected in series will be the sum of the three values.

Learn more about the equivalent resistance here:

brainly.com/question/11603204

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7 0
1 year ago
Starting from rest, a 6.79 kg block slides 2.82 m down a rough 20.7 ◦ incline. The coefficient of kinetic friction between the b
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Answer:

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Explanation:

m = Mass of block = 6.79 kg

s = Sliding distance = 2.82 m

\theta = Angle of slide = 20.7°

\mu = Coefficient of kinetic friction = 0.425

g = Acceleration due to gravity = 9.8 m/s²

Work done by the force of gravity is given by

W=mgsin\theta\\\Rightarrow W=6.79\times 9.8\times sin20.7\\\Rightarrow W=23.52092\ J

The work done by the force of gravity is 23.52092 J

8 0
3 years ago
For a photoelectric tube, calculate the voltage which will be just sufficient to stop electrons emitted by the sodium photo-plat
Talja [164]

Answer:

1.11 V

Explanation:

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E = energy of incident photon

Wo= work function of the metal

E = hf = 6.64 x 10-34 * 6 x 1014

E = 39.84 * 10^-20 J or 3.98  * 10^-19 J

KE = 3.98  * 10^-19 J - 2.2 x 10-19J

KE = 1.78 *  10^-19J

We convert this value of KE to electron volts

KE = 1.78 *  10^-19J/1.6 x 10-19C

KE = 1.11 eV

Hence; 1.11 V will be just sufficient to stop electrons emitted by the sodium photo-plate reaching the collector plate.

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One differnce between magnetic poles and elcyrical charges is that​
Sphinxa [80]

Answer:

In the electric field, the like charges repel each other, and the unlike charges attract each other, whereas in a magnetic field the like poles repel each other and the unlike poles attract each other.

Explanation:

8 0
3 years ago
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