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3 years ago

Which of the following is the reason a lever is used in a shovel?

Physics

2 answers:

storchak [24]3 years ago

8 0

The figure shown below illustrates a lever being used to lift a weight W.
The applied force is F.

In order to lift the weight, the minimum applied force is
F*b = W*a
F = (a/b)W

When the ratio a/b < 1, then the applied force is less than the weight.
The principle behind the use of a lever is to keep the ratio a/b small in order to decrease the effort force.

Answer: A
A lever is used to decrease effort force.

morpeh [17]3 years ago

4 0

<span>Which of the following is the reason a lever is used in a shovel?
</span><span>D. a lever is used to increase the effort force</span>

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Answer:

58.5 m

Explanation:

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$u_y = u sin \theta$

where

u = 21.5 m/s is the initial speed

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Substituting,

$u_y = (21.5) sin 33.5^{\circ} =11.9 m/s$

The vertical position of the ball at time t is given by

$y = h + u_y t + \frac{1}{2}gt^2$

where

h = 13.5 m is the initial heigth

$g = -9.8 m/s^2$ is the acceleration of gravity (negative sign because it points downward)

The ball reaches the water when y = 0, so

$0 = h + u_yt +\frac{1}{2}gt^2\\0 = 13.5 +11.9 t - 4.9t^2$

Which gives two solutions: t = 3.27 s and t = -0.84 s. We discard the negative solution since it is meaningless.

The horizontal velocity of the ball is

$u_y = u cos \theta = (21.5) cos 33.5^{\circ} =17.9 m/s$

And since the motion along the horizontal direction is a uniform motion, we can find the horizontal distance travelled by the ball as follows:

$d= u_x t = (17.9)(3.27)=58.5 m$

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3 years ago

A stone tumbles into a mine shaft strikes bottom after falling for 4.2 seconds. How deep is the mine shaft

ziro4ka [17]

$d = u \times t \: + \frac{1}{2} \times a \times {t}^{2}$
Since initial velocity is zero hence , u = 0

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3 years ago

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Answer:

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MA = Output force/Input force = 15 N/ 5 N = 3

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4 years ago

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Answer:

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