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3 years ago

The driver of a car slams on the brakes, causing the car to slow down at a rate of

Physics

1 answer:

sdas [7]3 years ago

7 0

Answer:

A. The time taken for the car to stop is 3.14 secs

B. The initial velocity is 81.64 ft/s

Explanation:

Data obtained from the question include:

Acceleration (a) = 26ft/s2

Distance (s) = 256ft

Final velocity (V) = 0

Time (t) =?

Initial velocity (U) =?

A. Determination of the time taken for the car to stop.

Let us obtain an express for time (t)

Acceleration (a) = Velocity (V)/time(t)

a = V/t

Velocity (V) = distance (s) /time (t)

V = s/t

a = s/t^2

Cross multiply

a x t^2 = s

Divide both side by a

t^2 = s/a

Take the square root of both side

t = √(s/a)

Now we can obtain the time as follow

Acceleration (a) = 26ft/s2

Distance (s) = 256ft

Time (t) =..?

t = √(s/a)

t = √(256/26)

t = 3.14 secs

Therefore, the time taken for the car to stop is 3.14 secs

B. Determination of the initial speed of the car.

V = U + at

Final velocity (V) = 0

Deceleration (a) = –26ft/s2

Time (t) = 3.14 sec

Initial velocity (U) =.?

0 = U – 26x3.14

0 = U – 81.64

Collect like terms

U = 81.64 ft/s

Therefore, the initial velocity is 81.64 ft/s

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3 years ago

Suppose a mad scientist went back in time to the beginning of the solar system and caused the newly formed Mars and Venus to swi

Black_prince [1.1K]

Answer:

Mars2 illuminated side of the planet is very heat, dark side very cool

Venus 2 a warm planet with a constant temperature across the entire surface

Explanation:

For this hypothetical case, when changing the planets they are changed with their current characteristics.

Case of Mars2

In this case, there is a planet with a very thin atmosphere, so the solar radiation reaches the ground without damping it, causing a lot of noise, so the illuminated side of the planet is very heat and when the dark side turns due to the little atmosphere it loses everything the heat for which it is very cold.

This thermal stress between the two sides of the planet continues constantly creating possible fruit trees in its rocky systems.

Case of Venus 2

The planet has a high atmospheric density, but it is very far from the sun, so the amount of radiation that arrives slightly warms the planet, but due to the thin atmosphere the losses for the dark period are very small, so the entire planet it is heated until it reaches an almost uniform temperature over its entire surface.

In this case we have a warm planet with a constant temperature across the entire surface, regardless of which side is lit.

8 0

3 years ago

You stand on a frictional platform that is rotating at 1.1 rev/s. Your arms are outstretched, and you hold a heavy weight in eac

bezimeni [28]

Answer:

a) The resulting angular speed of platform is 1.38 rev/sec

b) The change in kinetic energy of the system is 53 J.

Explanation:

This question is incomplete. The complete question will be:

You stand on a frictional platform that is rotating at 1.1 rev/s. Your arms are outstretched, and you hold a heavy weight in each hand. The moment of inertia of you, the extended weights, and the platform is 8.8 kg · m2. When you pull the weights in toward your body, the moment of inertia decreases to 7.0 k g .m 2

a) What is the resulting angular speed of the platform? Answer in units of r e v / s .

b)What is the change in kinetic energy of the system? Answer in units of J.

<h3>ANSWER:</h3>

we know that:

Angular Momentum = L = Iω

From conservation of momentum:

Lo = Lf

(Io) (ωo) = (If) (ωf)

ωf = (Io) (ωo)/(If)

ωf = (8.8 kg.m²)(1.1 rev/s)/(7.0 kg.m²)

ωf = (1.38 rev/sec)(2π rad/ 1 rev) = 8.67 rad/sec

ωo = (1.1 rev/sec)(2π rad/ 1 rev) = 6.91 rad/sec

The kinetic energy for rotational motion is given as:

K.E = (1/2)Iω²

Thus, the change in kinetic energy will be:

ΔK.E = (K.E)f - (K.E)o

ΔK.E = (1/2)Ifωf² - (1/2)Ioωo²

ΔK.E = (1/2)(Ifωf² - Ioωo²)

ΔK.E = (1/2)[(7 kg.m²)(8.67 rad/sec)² - (8.8 kg.m²)(6.91 rad/sec)²

5 0

3 years ago

When heat is removed from a substance , describe how the molecules are affected

kkurt [141]

I believe they would electron rate would slow down and the molecules would shrink.

I am almost positive that this is correct. I hope it helps!

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3 years ago

Read 2 more answers

Question 14 (2 points)

sveticcg [70]

Answer:

after 2 seconds its velocity is -20 m/s. after 3 seconds its velocity is -30 m/s. after 10 seconds its velocity is -100 m/s.

Explanation:

This is my answer.

7 0

3 years ago