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3 years ago

2000-kg car decelerated from 10 m/s to 5 m/s. What is the work done on the car ?

1 answer:

3 0

A 2000-kg car decelerated from 10 m/s to 5 m/s. What is the work done on the car ?

Known :

Car’s mass (m) = 2000 kg

Initial speed (vo) = 10 m/s

Final speed (vt) = 5 m/s

Wanted: net work

Solution :

Net work :

Wnet= ΔEK

Wnet = ½ m (vt2 – vo2)

Wnet = ½ (2000)(52 – 102)

Wnet = (1000)(25 – 100)

Wnet = (1000)(-75)

Wnet = -75,000 Joule

The minus sign indicates that the direction of displacement is opposite with the direction of the net force.

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What is a radio interferometer? a device for correcting chromatic aberration in radio telescopes a device for absorbing and tran

JulsSmile [24]

Answer: a network of several radio telescopes wired together

Explanation:

A radio interferometer combines signals of several radio telescopes which are used in astronomical observations simultaneously to simulate a discretely-sampled single telescope of very large aperture

Interferometer, an instrument that uses the interference patterns formed by waves to measure certain characteristics of the waves themselves or of materials that reflect, refract, or transmit the waves. Interferometers can also be used to make precise measurements of distance.

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3 years ago

Let the four horizontal compass directions north, east, south, and west be represented by units vectors n^, e^, s^, and w^, resp

Marrrta [24]

Answer:

c = e > b = d > a

Explanation:

Given vectors are all unit vectors, therefore they have a magnitude of 1

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As all are unit vectors their magnitude is 1 and therefore in this case the cross product between any two vectors depends on the sine of angle between those two vectors

In option a as both the vectors are same, the angle between them will be zero and sin0° will also be 0

In option b angle between those two vectors is 135° and sin135° is 1 ÷ √2

In option c angle between those two vectors is 90° and sin90° is 1

In option d angle between those two vectors is 45° and sin45° is 1 ÷ √2

In option e angle between those two vectors is 90° and sin90° is 1

So by comparison of magnitudes of cross products in each option, the order will be c = e > b = d > a

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3 years ago

A book falling to the floor is best described by: law one, law two, law three, or all three laws?

Law Incorporation [45]

The book falling to the floor is described by Newton's second law and Newton's third law

Explanation:

Newton's first law of motion states that:

"An object moving at constant velocity (or at rest) keeps moving at constant velocity (or will stay at rest) unless acted upon unbalanced, external forces"

For a book falling to the floor, there is an unbalanced force acting on it (the force of gravity): therefore, we cannot apply Newton's first law.

Newton's second law of motion states that:

"The net force acting on an object is equal to the product between the object's mass, m, and its acceleration, a"

Mathematically:

$F=ma$

For the book falling to the floor, F is the force of gravity; therefore, we can apply Newton's second law, and in this case it tells us that the book has a non-zero acceleration during its fall.

In particular, the force of gravity is $F=mg$ (where $g$ is the acceleration due to gravity), so the acceleration of the book is

$mg=ma\\a=g=9.8 m/s^2$

Newton's third law of motion states that:

"When an object A exerts a force (action force) on an object B, then object B exerts an equal and opposite force (reaction force) on object A".

In this case, the Earth is exerting a force (the force of gravity) on the book during its fall: therefore, the book is also exerting a equal and opposite force (reaction force) on the Earth.

Learn more about Newton laws of motion:

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4 years ago

Two cars, one of mass 1300 kg, and the second of mass 2400 kg, are moving at right angles to each other when they collide and st

Margarita [4]

To solve this problem we will apply the momentum conservation theorem, that is, the initial momentum of the bodies must be the same final momentum of the bodies. The value that will be obtained will be a vector value of the final speed of which the magnitude will be found later. Our values are given as,

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