Waves test please help!

Eddie the Eagle, British Olympic ski jumper, is attempting his most mediocre jump yet. After leaving the end of the ski ramp, he

sleet_krkn [62]

Answer:

Part a)

$v_f = 22.3 m/s$

Part b)

$\theta = 22.1 degree$

Part c)

$d = 11.7 m$

Explanation:

Velocity just before it strike the ground is given as

$v_x = 27 cos40$

$v_x = 20.7 m/s$

$v_y = 27 sin40$

$v_y = 17.36 m/s$

since there is no friction in horizontal direction so its speed in horizontal direction will remain same

Part a)

velocity in X direction

$v_x = 20.7 m/s$

time taken by the skier to reach the ground is given as

$v_x t = \Delta x$

$20.7 t = 54.4$

$t = 2.63 s$

now in the same time it will cover vertical distance

$v_y = v_{oy} + at$

$-17.36 = v_{oy} + (-9.81)(2.63)$

$v_{oy} = 8.42 m/s$

so magnitude of initial speed is given as

$v_f = \sqrt{v_x^2 + v_y^2}$

$v_f = \sqrt{20.7^2 + 8.42^2}$

$v_f = 22.3 m/s$

Part b)

Direction of velocity

$tan\theta = \frac{v_{oy}}{v_x}$

$tan\theta = \frac{8.42}{20.7}$

$\theta = 22.1 degree$

Part c)

Now in order to find the height of the ramp we can find the vertical displacement

$v_f^2 - v_y^2 = 2 a d$

$17.36^2 - 8.42^2 = 2(9.81)d$

$d = 11.7 m$

6 0

3 years ago

Tina is looking out a window and throws marble straight downward toward the sidewalk below at a speed of 5.00 m/s and the window

Katena32 [7]

Answer:

a) 28.1 m/s

b) 27.2 m

Explanation:

a)

Consider the motion of the marble in downward direction taking down direction as positive

v₀ = initial velocity = 5 m/s

v = final velocity as it hits the ground = ?

a = acceleration = 9.8 m/s²

d = vertical height traveled = 39 m

Using the equation

v² = v₀² + 2 a d

v² = 5² + 2 (9.8) (39)

v = 28.1 m/s

b)

t = time of travel = 1.90 s

y = vertical distance traveled

Using the equation

y = v₀ t + (0.5) a t²

y = (5)(1.90) + (0.5) (9.8) (1.90)²

y = 27.2 m

3 0

3 years ago

A charge Q is to be divided into two parts, labeled 'q' and 'Q-q? What is the relationship of q to Q if, at any given distance,

Lisa [10]

Answer:

Explanation:

The two charges are q and Q - q. Let the distance between them is r

Use the formula for coulomb's law for the force between the two charges

$F = \frac{Kq_{1}q_{2}}{r^{2}}$

So, the force between the charges q and Q - q is given by

$F = \frac{K\left ( Q-q \right )q}}{r^{2}}$

For maxima and minima, differentiate the force with respect to q.

$\frac{dF}{dq} = \frac{k}{r^{2}}\times \left ( Q - 2q \right )$

For maxima and minima, the value of dF/dq = 0

So, we get

q = Q /2

Now $\frac{d^{2}F}{dq^{2}} = \frac{-2k}{r^{2}}$

the double derivate is negative, so the force is maxima when q = Q / 2 .

6 0

4 years ago

Why do we use semiconductor instead of metal in thermopile?

serg [7]

Answer:

Metal or conductors , what they do is that they allow full flow of current that is conduction is due to free electrons only and there is literally no gap between valence and conduction band,so free electrons can easily jump into conduction band from valence band.

And now lets talk about insulators,what they do is that they don’t allow any current to flow i.e they act as strong dielectric,and gap between valence band and conduction band is so big that free electron can never come into conduction band from valence band ever if they try is for eternity…

But semiconductors can act both as an insulator as well as a conductor based on the voltage input. Hence, there is a possibility to control the current flow in semiconductors , so they don’t just relax and let the current pass by, they can control it, and that is why you can design logic circuits with it.

But as the temperature increases free electrons from valence band of insulators can jump to conduction band and can cause a little conductivity, and then the insulator will act as a semi-conductor.

6 0

3 years ago

Read the sentence. telescopes or satellites _____ that neither mercury nor venus _____ a moon. which pair of verb forms correctl

vredina [299]

When there is or in-between two words, the tense is dependent upon the word that comes after or. In other words, the word that is closest to the verb will decide the form of the verb.

Since satellites is a plural form of a satellite, the verb that follows <em>satellites</em> should also be plural. The plural verb in the given options is prove.

As far as the second blank is concerned, you can see Venus is a proper noun; therefore, the verb that comes after <em>Venus</em> should be a singular verb, which in this case is has.

So the complete sentence would become the following:

Telescopes and satellites prove that neither Mercury nor Venus has a moon.

Correct pair: prove:has

4 0

4 years ago

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