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vodka [1.7K]
3 years ago
10

A child in danger of drowning in a river is being carried down-stream by a current that flows uniformly with a speed of 2.20 m/s

. The child is 500 m from the shore and 1100 m upstream of the boat dock from which the rescue team sets out.
If their boat speed is 7.30 m/s with respect to the water, at what angle from the shore must the boat travel in order to reach the child?

Physics
1 answer:
zmey [24]3 years ago
5 0

Answer:

The angle is 65.6°.

Explanation:

Given that,

Speed = 2.20 m/s

Distance from the shore= 500 m

Distance from the bottom= 1100 m

Speed of boat = 7.30 m/s

According to figure,

We need to calculate the angle with shore

Using formula of angle

\tan\theta=\dfrac{y}{x}

Put the value into the formula

\tan\theta=\dfrac{500}{1100}

\theta=\tan^{-1}(\dfrac{500}{1100})

\theta=24.4^{\circ}

We need to calculate the angle

\alpha=90-\theta

Put the value into the formula

\alpha=90-24.4

\alpha=65.6^{\circ}

Hence, The angle is 65.6°.

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Gemiola [76]

Answer:

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Explanation:

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as the spaceship is moving away from earth so wavelength of earth should increase w.r.t increasing speed until it vanishes at λ'=700nm

using doppler shift's formula:

<em>λ'=λ°√(1+β/1-β)</em>

putting the values:

700nm=589nm√(1+β/1-β)

after simplifying:

<em>β=0.17</em>

by this we can say that speed at that time is: v=0.17c

to calculate velocity at an acceleration of a=29.4m/s²

we suppose that spaceship started from rest so,

<em>v=v₀+at</em>

where v₀=0

so<em> v=at</em>

as we want to calculate t so:-

<em>t=v/a</em>                                                v=0.17c      ,c=3x10⁸           ,a=29.4m/s²

putting values:

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3 years ago
How can the IMA of a first- class lever be increased?
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IMA = Ideal Mechanical Advantage

First class lever = > F1 * x2 = F2 * x1

Where F1 is the force applied to beat F2. The distance from F1 and the pivot is x1 and the distance from F2 and the pivot is x2

=> F1/F2 = x1 /x2

IMA = F1/F2 = x1/x2

Now you can see the effects of changing F1, F2, x1 and x2.

If you decrease the lengt X1 between the applied effort (F1) and the pivot,  IMA decreases.

If you increase the length X1 between the applied effort (F1) and the pivot, IMA increases.

If you decrease the applied effort (F1) and increase the distance between it and the pivot (X1) the new IMA may incrase or decrase depending on the ratio of the changes.

If you decrease the applied effort (F1) and decrease the distance between it and the pivot  (X1) IMA will decrease.

Answer: Increase the length between the applied effort and the pivot.
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3 years ago
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Consider three scenarios in which a particular box moves downward under the pull of gravity :
luda_lava [24]

Answer:

1. True  WA > WB > WC

Explanation:

In this exercise they give work for several different configurations and ask that we show the relationship between them, the best way to do this is to calculate each work separately.

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B) On a ramp without rubbing

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C) Ramp with rubbing

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When we review the affirmation it is the work where there is rubbing is the smallest and the work where it comes in free fall at the maximum

Let's review the claims

1. True The work of gravity is the greatest and the work where there is friction is the least

2 False. The job where there is friction is the least

3 False work with rubbing is the least

4 False work with rubbing is the least

5 0
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