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AfilCa [17]
3 years ago
15

The magnitude of the velocity vector of the car is ∣∣v→∣∣ = 78 ft/s. If the vector v→ forms an angle θ = 0.09 rad with the horiz

ontal direction, determine the Cartesian representation of v→ relative to the (iˆ, jˆ) component system.
Physics
1 answer:
kotegsom [21]3 years ago
3 0

Answer:

\vec{v} = (77.68~{\rm ft/s})\^i + (7.01~{\rm ft/s})\^j

Explanation:

The x- and y- components of the velocity vector can be written as following:

\vec{v}_x = ||\vec{v}||\cos(\theta)\^i

\vec{v}_y = ||\vec{v}||\sin(\theta)\^j

Since the angle θ and the magnitude of the velocity is given, the vector representation can be written as follows:

\vec{v} = 78\cos(0.09)\^i + 78\sin(0.09)\^j\\\vec{v} = (77.68~{\rm ft/s})\^i + (7.01~{\rm ft/s})\^j

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The right answer is c. You are going to divide by the velocity or speed by time.
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Answer:

Time taken = 10400 s

Explanation:

Given:

Initial speed of the train, u=72\textrm{ km/h}=72\times \frac{5}{18}=20\textrm{ m/s}

Final speed of the train, v=90\textrm{ km/h}=90\times \frac{5}{18}=25\textrm{ m/s}

Displacement of the train, S=234\textrm{ km}=234\times 1000=234000\textrm{ m}

Using Newton's equation of motion,

v - u = at\\a=\frac{v-u}{t}

Now, using Newton's equation of motion for displacement,

v^{2}-u^{2}=2aS

Now, plug in the value of a=\frac{v-u}{t} in the above equation. This gives,

v^{2}-u^{2}=2\times \frac{v-u}{t}\times S\\(v+u)(v-u)=\frac{2(v-u)S}{t}\\t=\frac{2(v-u)S}{(v+u)(v-u)}\\t=\frac{2S}{v+u}

Now, plug in 234000 m for S, 25 m/s for v and 20 m/s for u. Solve for t.

t=\frac{2S}{v+u}\\t=\frac{2\times 234000}{25+20}\\t=\frac{468000}{45}=10400\textrm{ s}

Therefore, the time taken by the train is 10400 s.

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Excellent human jumpers can leap straight up to a height of
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We can calculate the initial speed to reach 110 cm of height with the following equation:

v_{f}^{2} = v_{i}^{2} - 2gh

Where:

v_{f}: is the final speed = 0 (at the maximum height of 110 cm)

v_{i}: is the initial speed =?

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h: is the height = 110 cm = 1.10 m

Hence, the <u>initial velocity</u> is:

v_{i} = \sqrt{v_{f}^{2} + 2gh} = \sqrt{2*9.81 m/s^{2}*1.10 m} = 4.65 m/s

Therefore, the initial speed that the person must have to reach 110 cm is 4.65 m/s.

You can see another example here: brainly.com/question/13359681?referrer=searchResults

I hope it helps you!

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Therefore, if the ship speed is doubled, then the power developed is 8 times the initial value.

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