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siniylev [52]
3 years ago
11

A person stands at rest on a slope which makes an angle 25 degrees to the horizontal. They have a mass of 71 kg. They start to r

un up the slope. After a time of
9.9 s they reach a distance 29 m up the slope and have a velocity of 4.7 m/s.
(a) Calculate the vertical height gained.
select units
(b) Determine how much energy the person has used.
select units
(c) Calculate the average power output of the person.
select units
Physics
2 answers:
Bezzdna [24]3 years ago
7 0

Answer:

a) 12.2559 m

b) 9320.5519 J

c) 941.4699 W

Explanation:

a) Use sine to find vertical height.

sinθ = opposite/hypotenuse

∴ sin25 = h/29

∴ h = 29 (sin25) = 12.25592959 metres

b) Find mechanical energy using potential and kinetic energy.

Total energy used is mechanical energy. Menchanical energy (E) is equal to potential energy (U=mgh) plus kinetic energy (K= (0.5)m v²).

E = U + K

= mgh + (0.5)m v²

= (71)(9.81)(12.2559) + (0.5)(71)(4.7²)

= 8536.356909 + 784.195

= 9320.551909 Joules

c) Find power using answer from part b

Power = energy / time elapsed

= 9320.5519/9.9

= 941.4698898 Watts

Lemme know if you have any questions :)

Komok [63]3 years ago
6 0
It’s C because I took the test and got it right
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Answer:

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The final velocity is greater than the velocity used to find the average acceleration due to the gear changes. The first gear in a dragster has the most amount of toque which means the acceleration will be maximum. The final gears have less torque which means the acceleration is lower here. The final gears have less acceleration but can spin faster which makes the dragster able to reach higher speeds but slowly.

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3 years ago
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Answer:

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Explanation:

From the question we are told that

    The  Poynting vector (energy flux ) is  k  =  0.939 \ W/m^2

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The total electromagnetic energy falls on the area is mathematically represented as

      T  =  k  *  A  *  t

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 substituting values

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substituting values

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