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uysha [10]
3 years ago
9

A 200. Kg load of bricks is to be lifted from the ground to the top of a 30.0 m high building in 30.0 s. If a 75.0 N frictional

force in the pulley opposes motion, what minimum power motor would be needed?
Physics
1 answer:
coldgirl [10]3 years ago
3 0

Answer:

The minimum power the motor would need is 2035 Watts.

Explanation:

the minimum power motor needed is given by the total work done on the load, Wtot and the total time it takes the load to be lifted, given by:

P = Wtot/t

the forces doing works on the load is the gravitational force, Wfg and the frictional force, Wf the total work done on the load is:

Wtot = Wfg + Wf

        =  m×g×d + f×d

        = d×(m×g + f)

        = (30)×(200×9.8 + 75)

         = 61050 J

it takes t = 30s for the load to be lifted high the building, the minimum power neeed is then:

P = Wtot/t

  = (61050)/(30)

  = 2035 Watts

Therefore, the minimum power the motor would need is 2035 Watts.

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A cheerleader lifts his 79.4 kg partner straight up off the ground a distance of 0.945 m before releasing her. the acceleration
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Given the vector A with components Ax = 2.00, Ay = 6.00, the vector B with components Bx = 2.00, By = 22.00, and the vector D =
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Answer:

<em>The magnitude of vector d is 16 and the angle with the x-axis is 270°</em>

Explanation:

<u>Operations With Vectors</u>

Given two vectors in rectangular components:

\vec a=(ax,ay)\ ,\  \vec b=(bx,by)

The sum of the vectors is:

\vec a+\vec b=(ax+bx,ay+by)

The difference between the vectors is:

\vec a-\vec b=(ax-bx,ay-by)

The magnitude of \vec a is:

|\vec a|=\sqrt{ax^2+ay^2}

The angle \vec a makes with the horizontal positive direction is:

\displaystyle \tan\theta=\frac{ay}{ax}\\

The question provides the vectors:

\vec a=(2,6)

\vec b=(2,22)

\vec d=\vec a-\vec b

Calculate:

\vec d=(2,6)-(2,22)=(0,-16)

The magnitude of \vec d is:

|\vec d|=\sqrt{0^2+(-16)^2}=\sqrt{0+256}=16

The angle is calculated by:

\displaystyle \tan\theta=\frac{-16}{0}

The division cannot be calculated because the denominator is zero. We need to estimate the correct angle by looking at the components of the vector. Since the x-coordinate is zero and the y-coordinate is negative, the vector points downwards (south), thus the angle must be -90° or 270° if the range goes from 0° to 360°.

The magnitude of vector d is 16 and the angle with the x-axis is 270°

4 0
3 years ago
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