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2 years ago

15

A car starts with an initial speed of 12 m/s and accelerates at 3 m/s/s for 5 seconds

1 answer:

Nostrana [21]2 years ago

3 0

Explanation:

Vi = 12 m/s

a = 3 m/s^2

t = 2 s

Vf = Vi + a × t = 12 + 3 ×2 = 18 m/s

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HELP PLEASE 20 POINTS SHOW WORK, ALL EQUATIONS

nataly862011 [7]

Answer:

s = 3 m

Explanation:

Let t be the time the accelerating car starts.

Let's assume the vehicles are point masses so that "passing" takes no time.

the position of the constant velocity and accelerating vehicles are

s = vt = 40(t + 2) cm

s = ½at² = ½(20)(t)² cm

they pass when their distance is the same

½(20)(t)² = 40(t + 2)

10t² = 40t + 80

0 = 10t² - 40t - 80

0 = t² - 4t - 8

t = (4±√(4² - 4(1)(-8))) / 2(1)

t = (4± 6.928) / 2 ignore the negative time as it has not occurred yet.

t = 5.464 s

s = 40(5.464 + 2) = 298.564 cm

300 cm when rounded to the single significant digit of the question numerals.

7 0

3 years ago

The current theory of the structure of the Earth, called plate tectonics, tells us that the continents are in constant motion.

lesya [120]

Answer:

(a) m = 1.6 x 10²¹ kg

(b) K.E = 2.536 x 10¹¹ J

(c) v = 7.12 x 10⁵ m/s

Explanation:

(a)

First we find the volume of the continent:

V = L*W*H

where,

V = Volume of Slab = ?

L = Length of Slab = 4450 km = 4.45 x 10⁶ m

W = Width of Slab = 4450 km = 4.45 x 10⁶ m

H = Height of Slab = 31 km = 3.1 x 10⁴ m

Therefore,

V = (4.45 x 10⁶ m)(4.45 x 10⁶ m)(3.1 x 10⁴ m)

V = 6.138 x 10¹⁷ m³

Now, we find the mass:

m = density*V

m = (2620 kg/m³)(6.138 x 10¹⁷ m³)

<u>m = 1.6 x 10²¹ kg</u>

<u></u>

(b)

The kinetic energy will be:

K.E = (1/2)mv²

where,

v = speed = (1 cm/year)(0.01 m/1 cm)(1 year/365 days)(1 day/24 h)(1 h/3600 s)

v = 3.17 x 10⁻¹⁰ m/s

Therefore,

K.E = (1/2)(1.6 x 10²¹ kg)(3.17 x 10⁻¹⁰ m/s)²

<u>K.E = 2.536 x 10¹¹ J</u>

<u></u>

(c)

For the same kinetic energy but mass = 77 kg:

K.E = (1/2)mv²

2.536 x 10¹¹ J = (1/2)(77 kg)v²

v = √(2)(2.536 x 10¹¹ J)

<u>v = 7.12 x 10⁵ m/s</u>

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3 years ago

How does adding more of a substance affect it's density?

fomenos

I’m going to use molasses as an example of a substance.

The mass and volume both change when changing the amount of molasses.
However, the density does not change. This is because the mass and volume increase at the same rate/proportion!

Even though there is more molasses (mass) in test tube A, the molasses also takes up more space (volume). Therefore, the spacing between those tiny particles that make up the molasses is constant (does not change).

The size or amount of a material/substance does not affect its density.

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3 years ago

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The heat energy gained by the water in one minute is ?

kari74 [83]

<span>fast-moving particles colliding with slow-moving particles</span>

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3 years ago

Questlon 20 of 20 Which change to an object would quadruple its kinetic energy?

worty [1.4K]

Answer:Questlon 20 of 20 Which change to an object would quadruple its kinetic energy?

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D. Increasing its mass to twice its original value Questlon 20 of 20 Which change to an object would quadruple its kinetic energy?

A. Reducing its mass to one-half of its original value

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A. Reducing its mass to one-half of its original value

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C. Reducing its velocity to one-half of its original value O

D. Increasing its mass to twice its original value Questlon 20 of 20 Which change to an object would quadruple its kinetic energy?

A. Reducing its mass to one-half of its original value

B. Increasing its velocitato twice its original value

C. Reducing its velocity to one-half of its original value O

D. Increasing its mass to twice its original value Questlon 20 of 20 Which change to an object would quadruple its kinetic energy?

A. Reducing its mass to one-half of its original value

B. Increasing its velocitato twice its original value

C. Reducing its velocity to one-half of its original value O

D. Increasing its mass to twice its original value Questlon 20 of 20 Which change to an object would quadruple its kinetic energy?

A. Reducing its mass to one-half of its original value

B. Increasing its velocitato twice its original value

C. Reducing its velocity to one-half of its original value O

D. Increasing its mass to twice its original value Questlon 20 of 20 Which change to an object would quadruple its kinetic energy?

A. Reducing its mass to one-half of its original value

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C. Reducing its velocity to one-half of its original value O

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A. Reducing its mass to one-half of its original value

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C. Reducing its velocity to one-half of its original value O

D. Increasing its mass to twice its original value Questlon 20 of 20 Which change to an object would quadruple its kinetic energy?

A. Reducing its mass to one-half of its original value

B. Increasing its velocitato twice its original value

C. Reducing its velocity to one-half of its original value O

D. Increasing its mass to twice its original value Questlon 20 of 20 Which change to an object would quadruple its kinetic energy?

A. Reducing its mass to one-half of its original value

B. Increasing its velocitato twice its original value

C. Reducing its velocity to one-half of its original value O

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Explanation:

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3 years ago

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