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Mekhanik [1.2K]
3 years ago
13

You are testing a new amusement park roller coaster with an empty car with a mass 120 kg. One part of the track is a vertical lo

op with radius 12.0 m. At the bottom of the loop(part A) the car has a speed 25.0 m/s and at the top of the loop (point B) has a speed of 8.0 m/s. As the car rolls from point A to point B, how much work is done by friction.
Physics
1 answer:
Kay [80]3 years ago
4 0

Answer:

- 5436 J

Explanation:

mass of car, m = 120 kg

radius of loop, r = 12 m

velocity at the bottom (A) = Va = 25 m/s

Velocity at the top(B) = Vb = 8 m/s

Vertical distance from A to B = diameter of loop, h = 2 x 12 = 24 m

by use of Work energy theorem

Work done by all the forces = change in kinetic energy of the body

Work done by the force + Work done by the friction = Kinetic energy at B - kinetic energy at A

- m x g x h + Work done by friction = 0.5 x 120 x (Vb^2 - Va^2)

- 120 x 9.8 x 24 + Work done by friction = 60 x (64 - 625)

- 28224 + Work done by friction = - 33660

Work done by friction = -33660 + 28224 = - 5436 J

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Answer:

The maximum height above the point of release is 11.653 m.

Explanation:

Given that,

Mass of block = 0.221 kg

Spring constant k = 5365 N/m

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Using stored energy in spring

U=\dfrac{1}{2}kx^2...(I)

Using gravitational potential energy

U' =mgh....(II)

Using energy of conservation

E_{i}=E_{f}

U_{i}+U'_{i}=U_{f}+U'_{f}

\dfrac{1}{2}kx^2+0=0+mgh

h=\dfrac{kx^2}{2mg}

Where, k = spring constant

m = mass of the block

x = distance

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Put the value in the equation

h=\dfrac{5365\times(0.097)^2}{2\times0.221\times9.8}

h=11.653\ m

Hence, The maximum height above the point of release is 11.653 m.

3 0
3 years ago
Red, green, and blue light rays each enter a drop of water from the same direction.Which light ray's path through the drop will
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Blue light will bend more than the others because it has a slightly greater refractive index. This is because blue light has a shorter wavelength and more energy, meaning it has to slow down more than the others when it hits the water.
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kifflom [539]

Answer:

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Explanation:

Given data

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The Newton is derived because mass, distance, and time are all fundamental units One would have to look at the fundamental requirements for these definitions, but they can all be repeated in a laboratory.

So the Newton is determined from these fundamental units and since the Joule equals Newton * Distance it is also derived from the fundamental units.

If one has the three fundamental units then one can derive the Joule and Newton.

3 0
3 years ago
During a circus act, an elderly performer thrills the crowd by catching a cannon ball shot at him. The cannon ball has a mass of
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