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3 years ago

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During a race, a runner runs at a speed of 6 m/s. Four seconds later, she is running at a speed of 10 m/s. what is the runners a

cceleration? show your work.

1 answer:

Georgia [21]3 years ago

8 0

<span>a = (v2 - v1)/t = (10 - 6)/2 = 2 m/sec/sec (average acceleration)</span>

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A pendulum consists of a 2.7 kg stone swinging on a 4.0 m string of negligible mass. The stone has a speed of 8.1 m/s when it pa

Brut [27]

Answer:

a). v=4.77 $\frac{m}{s}$

b). β=80.61

c). E=88.5J

Explanation:

a).

$m1=2.7 kg\\L=4m\\v_{1}=8.1 \frac{m}{s}\\\beta=63$

$\frac{m*v_{1} ^{2} }{2}+m*g*y_{1}=\frac{m*v_{2}^{2} }{2}+m*g*y_{2}\\\frac{m*v_{1} ^{2} }{2}=\frac{m*v_{2}^{2} }{2}+m*g*y_{2}\\v_{2}=\sqrt{v_{1}^{2}-2*g*y_{2}}\\y_{2} =L-L*cos(\beta)\\v_{2}=\sqrt{v_{1}^{2}-2*g*(L-L*cos(\beta))}\\v_{2}=\sqrt{8.1^{2}-2*9.8*(4(1-*cos(63))}\\v_{2}=\sqrt{8.1^{2}-42.8}\\v_{2}=\sqrt{64-42.8}\\v_{2}=\sqrt{21.19}=4.77 \frac{m}{s}$

b).

$\frac{m*v_{1}^{2}}{2} +m*y_{1} =\frac{m*v_{2}^{2}}{2} +m*y_{2}\\\frac{m*v_{1}^{2}}{2} +0 =0 +m*y_{2}\\y_{2}=\frac{v_{1}^{2}}{2*g}=\frac{(8.1^\frac{m}{s}){2}}{2*9.8\frac{m}{s^{2} }}=3.34 m\\ 3.34m=L(1-cos(\alpha)\\3.34m=4*(1-cos(\alpha ))\\cos(\alpha )=\frac{4-3.34}{4}=0.16\\(\alpha )= cos^{-1}*(0.163)\\ (\alpha )= 80.61$

c).

$E=\frac{m*v_{1} ^{2} }{2}\\ E=\frac{(2.7kg)*(8.1\frac{m}{s})^{2}}{2}=\frac{177.147\frac{kg*m^{2}}{s^{2}}}{2}\\\\E=88.5 J$

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3 years ago

It takes 1 molecule of nitrogen and 3 molecules of hydrogen to produce 2 molecules of ammonia using the following formula:

fgiga [73]

Here, we are required to determine which combination of molecules will produce ammonia with no leftovers.

Option A: 2N2 and 6H2 is the correct combination of molecules that will produce ammonia with no leftovers.

First, it is important to know that both Nitrogen and Hydrogen used in the production of ammonia are diatomic.

Secondly, Nitrogen and Hydrogen are in the ratio 1 : 3.....

As such, the coefficient of hydrogen should be thrice that of Nitrogen to ensure that there are no leftovers.

Therefore, option A which has:

2N2 and 6H2 is the correct combination of molecules that will produce ammonia with no leftovers.

Read more:

brainly.com/question/24396848

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2 years ago

Why is friction needed?

Anastasy [175]

$\Huge\mathfrak {Answer}$

Friction is a contact force which always opposes the relative motion. There are three types of friction.

Friction is necessary in every aspects of living such as while walking we need friction.

Thanks

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3 years ago

What is the car’s average velocity (slope) between “O” and “A”? (y2-y1 / x2-x1) = slope

bija089 [108]

Please find the attached photograph for your answer. Hope it helps! Please do comment

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3 years ago

Why are Physical changes Not represented by Equations

solmaris [256]

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3 years ago

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