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3 years ago

A car accelerates at a constant rate from 12 m/s to 27 m/s while it travels 125 m. How long does it take to achieve this speed?

Physics

1 answer:

MArishka [77]3 years ago

3 0

Answer:

6.41 s

Explanation:

Under constant acceleration we know that

average velocity × time taken = displacement

$s=\frac{u+v}{2}t$

$125=\frac{27+12}{2}t$

t = 6.41 s

The proof of used equation is given in the attachment.

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A hot air balloon is traveling vertically upward at a constant speed of 4.5 m/s. When it is 28 m above the ground, a package is

ella [17]

Answer:

1.97 seconds

Explanation:

t = Time taken

u = Initial velocity

v = Final velocity

s = Displacement

a = Acceleration due to gravity = 9.8 m/s²

$s=ut+\frac{1}{2}at^2\\\Rightarrow 21=4.5t+\frac{1}{2}\times -9.8\times t^2\\\Rightarrow 21=-4.5t-4.9t^2\\\Rightarrow 4.9t^2+4.5t-28=0\\\Rightarrow 49t^2+45t-280=0$

Solving the above equation we get

$t=\frac{-45+\sqrt{45^2-4\cdot \:49\left(-280\right)}}{2\cdot \:49}, \frac{-45-\sqrt{45^2-4\cdot \:49\left(-280\right)}}{2\cdot \:49}\\\Rightarrow t=1.97, -2.89$

So, the time the package was in the air is 1.97 seconds

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3 years ago

When an astronomer sees certain stars and galaxies that look much redder than expected, what conclusion might the astronomer dra

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What is the role of neutrons in an atom?

mihalych1998 [28]

Hihi!

The correct answer is B) neutron keep protons apart so they don’t repel
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I hope I helped!
-Jailbaitasmr

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e force acting between two charged particles A and B is 5.2 × 10-5 newtons. Charges A and B are 2.4 × 10-2 meters apart. If the

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The force acting between the particles is

$F=k \frac{Q_{1}Q_{2}}{r^2}$
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What does basketballs have inside of it

FrozenT [24]

Hi there!

Great question!

Basketballs have air inside them. A special pump is used to insert the air. That's why you can lift the basketballs off the ground easily. If it was a solid, though, you'd hardly be able to lift the ball up! Basketballs can float, too, because anything with air inside can float. If it were solid, it would sink in the water easily.

Hope this helps! :D

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3 years ago