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iragen [17]
2 years ago
11

A 110-pound person pulls herself up 4.0 feet. This took her 2.5 seconds. How much power was developed?

Physics
2 answers:
mrs_skeptik [129]2 years ago
5 0

Answer:

0.32 Hp is the answer. right

lesya [120]2 years ago
4 0

Answer: Power developed by her is <u><em>0.32 hp</em></u>

 

Explanation:

Work done , W= Force(F) X Displacement (d) in the direction of force

Thus work done , W=Fd=110\times 4.0 ft-lbf = 440 ft-lbf

Now 1.0 ft-lbf = 1.355 joules of energy

Therefore , work done, W= 440x 1.355 J = 596.2 J

Average Power , P=\frac{work done(W)}{time (t)}

=> P=\frac{596.2}{2.5} watts = 238.5 watts

We know 746 hp = 1.0 watts

=> P=\frac{238.5}{746} hp=0.32 hp

Thus average power developed by her is 0.32 hp

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A 1.15-kg mass oscillates according to the equation x = 0.650 cos(8.40t) where x is in meters and t in seconds. Determine (a) th
zheka24 [161]

Answer:

(a) A = 0.650 m

(b) f = 1.3368 Hz

(c) E = 17.1416 J

(d)  K = 11.8835 J

     U = 5.2581 J

Explanation:

Given

m = 1.15 kg

x = 0.650 cos (8.40t)

(a) the amplitude,

A = 0.650 m

(b) the frequency,

if we know that

ω = 2πf = 8.40    ⇒   f = 8.40 / (2π)

⇒   f = 1.3368 Hz

(c) the total energy,

we use the formula

E = m*ω²*A² / 2

⇒  E = (1.15)(8.40)²(0.650)² / 2

⇒  E = 17.1416 J

(d) the kinetic energy and potential energy when x = 0.360 m.

We use the formulas

K = (1/2)*m*ω²*(A² - x²)       (the kinetic energy)

and

U = (1/2)*m*ω²*x²              (the potential energy)

then

K = (1/2)*(1.15)*(8.40)²*((0.650)² - (0.360)²)

⇒  K = 11.8835 J

U = (1/2)*(1.15)*(8.40)²*(0.360)²

⇒  U = 5.2581 J

4 0
2 years ago
Jeff puts on a leather jacket over his sweater. The sweater becomes negatively charged. Which statements about Jeff’s situation
Vinil7 [7]

Following statements are true
(i) The leather jacket has a lower tendency to attract electrons than sweater.
When the sweater and the leather jacket are in contact with each other, the leather jacket loses electrons and thus becomes positively charged. the electrons are gained by the sweater and it becomes negatively charges.
The opposite charge attract. so the sweater ( negatively charged) will attract protons ( positively charged) . The leather jacket ( positively charged) will attract the electrons ( negatively charged).

7 0
2 years ago
Read 2 more answers
Which changes in an electric motor will make the motor stronger? Check all that apply. using a stronger permanent magnet using a
miv72 [106K]
Use stronger magnets
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4 0
2 years ago
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A ship 1200m off shore fires a gun. how long after the gun is fired will it be heard on the shore?​
ryzh [129]

Answer:

We know that the speed of sound is 343 m/s in air

we are also given the distance of the boat from the shore

From the provided data, we can easily find the time taken by the sound to reach the shore using the second equation of motion

s = ut + 1/2 at²

since the acceleration of sound is 0:

s = ut + 1/2 (0)t²

s = ut    <em>(here, u is the speed of sound , s is the distance travelled and t is the time taken)</em>

Replacing the variables in the equation with the values we know

1200 = 343 * t

t = 1200 / 343

t = 3.5 seconds (approx)

Therefore, the sound of the gun will be heard at the shore, 3.5 seconds after being fired

6 0
2 years ago
A mineral deposit along a strip of length 8 cm has density s(x) = 0.01x(8 − x) g/cm for 0 ≤ x ≤ 8. Calculate the total mass of t
vazorg [7]

Answer:

8z

Explanation:

It is 8z

3 0
2 years ago
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