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Tomtit [17]
2 years ago
11

The velocity of a sky diver t seconds after jumping is given by v(t) = 80(1 − e−0.2t). After how many seconds is the velocity 65

ft/s? (Round your answer to the nearest whole number.)
Physics
1 answer:
Fed [463]2 years ago
8 0

Answer:

8 seconds

Explanation:

Given:

The velocity of the sky diver 't' seconds after jumping is given as:

v(t)=80(1-e^{-0.2t})

The velocity is given as, v=65\ ft/s

So, in order to find the time required to reach the above given velocity, we plug in 65 for 'v' in the above equation and solve for time 't'. This gives,

65=80(1-e^{-0.2t})\\\\\frac{65}{80}=1-e^{-0.2t}\\\\0.8125=1-e^{-0.2t}\\\\e^{-0.2t}=1-0.8125\\\\\textrm{Taking natural log on both sides, we get:}\\\\-0.2t=\ln(0.1875)\\\\t=\frac{\ln(0.1875)}{-0.2}\\\\t=8.4\ s\approx 8\ s(Nearest\ whole\ number)

Therefore, the time taken to reach a velocity of 65 ft/s is nearly 8 seconds.

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This would be gas, due to it not essentially having a definite volume.

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Carbon-14 has a half-life of 5,730 years. if the age of an object older than 50,000 years cannot be determined by radiocarbon da
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<h3><u>Answer;</u></h3>

Carbon-14 levels in a sample are undetectable after approximately 9 half lives

<h3><u>Explanation;</u></h3>
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<em><u>  50,000÷5,730 </u></em>

<em><u>= 8.73 half lives</u></em>

<em>Which is approximately equal to 9 half lives.</em>

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6 0
2 years ago
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To pull a nail out of a wood board a carpenter does 1000 J of work. The hammer he uses does 835 J of work. What is the efficienc
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83.5%

Explanation:

7 0
3 years ago
Need Help !
Bad White [126]

Answer: 5.96m/s

Explanation:

Given the following :

Mass of car (m) = 1500kg

Velocity (V) = 5.25m/s

Forward force of engine = 1250N

Diatance moved = 4.8m

Final Velocity =?

Final kinetic energy = Initial kinetic energy + work done by engine

Initial kinetic energy = 0.5 × mass × velocity^2

Initial kinetic energy = 0.5 × 1500 × 5.25^2

Initial kinetic energy = 20671.875 J

Work done by engine = Force × distance

Work done by engine = 1250 × 4.8 = 6000J

Final kinetic energy = (20671.875 + 6000) J

= 26671.875 J

From kinetic energy = 0.5mv^2

26671.875 = 1/2 × 1500 × v^2

53343.75 = 1500v^2

v^2 = 35.5625

v = sqrt(35.5625)

v = 5.96m/s

3 0
2 years ago
Which of these objects must have the greatest force acting on it? pls help fast
8_murik_8 [283]

Let's look at Newton's second law

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Force is directly proportional towards mass

If mass is more force will be more.

Between baseball and bowling ball Bowling ball has higher mass

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Option D

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