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3 years ago

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a 320-foot tree casts a 130-foot shadow on horizontal ground. a girl lying on the grass at the tip of the shadow is looking at a

bird nesting at the top of the tree. at what angle is the girl looking up? assume that the tree grows at a right angle to the ground g

1 answer:

mixer [17]3 years ago

7 0

Answer: $\theta =67.88^{\circ}$

Explanation:

Given

Height of tree is H=320 ft

length of shadow L=130 ft

let $\theta$ be the angle of elevation

using trigonometric relation

$\tan \theta =\frac{H}{L}$

$\tan \theta =\frac{320}{130}$

$\theta =tan^{-1}(2.461)$

$\theta =67.88^{\circ}$

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What is the speed of a vehicle with a distance of 88 miles and a time of 4 hours????

Tanya [424]

The answer you are looking for is 22 mph.

Solution:

s=speed

d=distance

t=time

Setting up the formula for the speed of an object with distance and time:

s=d/t

Substituting the given values,

s=88 miles/4 hours

So, therefore, the final answer is 22 mph.

I hope this helped answer your question for you. Good day to you.

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3 years ago

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Answer: Cluster 3 (D)

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4 years ago

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a proton of mass 1 u travelling with a speed of 3.6 x 10 ^4 m/s has an elastic head on collision with a helium nucleus initially

CaHeK987 [17]

Answer:

Velocity of the helium nuleus = 1.44x10⁴m/s

Velocity of the proton = 2.16x10⁴m/s

Explanation:

From the conservation of linear momentum of the proton collision with the He nucleus:

$P_{1i} + P_{2i} = P_{1f} + P_{2f]$ (1)

<em>where $P_{1i}$ : is the proton linear momentum initial, $P_{2i}$ : is the helium nucleus linear momentum initial, $P_{1f}$ : is the proton linear momentum final, $P_{2f}$ : is the helium nucleus linear momentum final </em>

<u>From (1):</u>

$m_{1}v_{1i} + 0 = m_{1}v_{1f} + m_{2}v_{2f}$ (2)

<em>where m₁ and m₂: are the proton and helium mass, respectively, $v_{1i}$ and $v_{2i}$ : are the proton and helium nucleus velocities, respectively, before the collision, and $v_{1f}$ and $v_{2f}$ : are the proton and helium nucleus velocities, respectively, after the collision </em>

By conservation of energy, we have:

$K_{1i} + K_{2i} = K_{1f} + K_{2f}$ (3)

<em>where $K_{1i}$ and $K_{2i}$ : are the kinetic energy for the proton and helium, respectively, before the colission, and $K_{1f}$ and $K_{2f}$ : are the kinetic energy for the proton and helium, respectively, after the colission </em>

<u>From (3):</u>

$\frac{1}{2}m_{1}v_{1i}^{2} + 0 = \frac{1}{2}m_{1}v_{1f}^{2} + \frac{1}{2}m_{2}v_{2f}^{2}$ (4)

<u>Now we have two equations: (2) ad (4), and two incognits: $v_{1f}$ and $v_{2f}$ . </u>

Solving equation (2) for $v_{1f}$ , we have:

$v_{1f} = v_{1i} -\frac{m_{2}}{m_{1}} v_{2f}$ (5)

<u>From getting (5) into (4) we can obtain the $v_{2f}$ :</u>

$v_{2f}^{2} \cdot (\frac{m_{2}^{2}}{m_{1}} + m_{2}) - 2v_{2f}v_{1i}m_{2} = 0$

$v_{2f}^{2} \cdot (\frac{(4u)^{2}}{1u} + 4u) - v_{2f}\cdot 2 \cdot 3.6 \cdot 10^{4} \cdot 4u = 0$

From solving the quadratic equation, we can calculate the velocity of the helium nucleus after the collision:

$v_{2f} = 1.44 \cdot 10^{4} \frac{m}{s}$ (6)

Now, by introducing (6) into (5) we get the proton velocity after the collision:

$v_{1f} = 3.6 \cdot 10^{4} -\frac{4u}{1u} \cdot 1.44 \cdot 10^{4}$

$v_{1f} = -2.16 \cdot 10^{4} \frac{m}{s}$

The negative sign means that the proton is moving in the opposite direction after the collision.

I hope it helps you!

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4 years ago

How should the goals of a beginner differ from someone who is more advanced?

nevsk [136]

Hi!

A beginner is less skilled than someone who is more advanced, and has, in most cases, less experience.

Therefore, if they each set realistic goals for their skill levels, a beginner will have less, adventurous (for lack of a better word) goals because the beginner knows they can achieve less, while an advanced person would set higher goals that are more difficult to achieve, but realistic for themselves.

Hope this helped!

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3 years ago

A 100 kg father and his 50 kg daughter stand on ice skates on a frozen pond. The daughter pushes on her father with a force of 5

Lana71 [14]

Answer:

Both feel same magnitude force.

Explanation:

Given that

Mass of father = 100 kg

Mass of daughter = 50 kg

From the third law of Newtons :

Every action have it reaction in opposite direction.It means that if any object apply a force on the other object then first object also feel force of same magnitude but in opposite direction.

It means that both father and her daughter will feel same magnitude of same but in opposite direction.

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4 years ago

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