Which refers to the number of wavelengths that pass a fixed point in a second?

Which of the following statements is true about tides? (2 points)

andre [41]

1: Tides are caused by the location of the Earth, sun, and moon.

2: Tides occur about an hour later each day.
This is because of the earth's orbit and the moons position as they move.

3: Half as much as the moon
The moon affects the tide much more than the sun, as the moon is drastically closer to the earth than the sun.

4 0

3 years ago

I would like help with this physics problem

Darina [25.2K]

(a) This is a freefall problem in disguise - when the ball returns to its original position, it will be going at the same speed but in the opposite direction. So the ball's final velocity is the negative of its initial velocity.

Recall that

$v_f=v_i+at$

We have $v_f=-v_i$ , so that

$-2v_i=at\implies-2\left(8\,\dfrac{\mathrm m}{\mathrm s}\right)=\left(-2\,\dfrac{\mathrm m}{\mathrm s^2}\right)t\implies t=8\,\mathrm s$

(b) The speed of the ball at the start and at the end of the roll are the same 8 m/s, so the average speed is also 8 m/s.

(c) The ball's average velocity is 0. Average velocity is given by $\dfrac{v_i+v_f}2$ , and we know that $v_f=-v_i$ .

(d) The position of the ball $x_f$ at time $t$ is given by

$x_f=x_i+v_it+\dfrac12at^2$

Take the starting position to be the origin, $x_i=0$ . Then after 6 seconds,

$x_f=\left(8\,\dfrac{\mathrm m}{\mathrm s}\right)(6\,\mathrm s)+\dfrac12\left(-2\,\dfrac{\mathrm m}{\mathrm s^2}\right)(6\,\mathrm s)^2=42\,\mathrm m$

so the ball is 42 m away from where it started.

We're not asked to say in which direction it's moving at this point, but just out of curiosity we can determine that too:

$x_f-x_i=\dfrac{v_i+v_f}2t\implies42\,\mathrm m=\dfrac{8\,\frac{\mathrm m}{\mathrm s}+v_f}2(6\,\mathrm s)\implies v_f=6\,\dfrac{\mathrm m}{\mathrm s}$

Since the velocity is positive, the ball is still moving up the incline.

8 0

2 years ago

What are the directions of movement for the Sagittarius, frontal, transverse planes ?

Dima020 [189]

Answer:

Squats involve flexion (forward motion) and extension (backward on the way up), so would fit into the sagittal plane. Frontal plane motion would include leaning from left to right as in sidebends and lateral raises, or perhaps you might picture jumping jacks for a good image of movement along the frontal plane.

5 0

3 years ago

A kayaker moves 32 meters northward then 6 meters southward finally 24 meters northward

azamat

Answer:

50m [N]

Explanation:

Think of these directions as if they were on a 2D plane. (if you're talking about displacement)

If you go 32m [N] then 6m [S], it's like you're moving backwards (-). (thus, 32n-6s=26m [N])

Next, you go north again, so moving forwards (+). (thus, 26n+24n=50m [N])

5 0

2 years ago

Read 2 more answers

Eye at the lowest radiated power of 1,2 x10 x (- 17) W. Determine how many photons of light with a wavelength of 500nm fall on t

mars1129 [50]

Answer:

$\frac{n}{t} = 30\ photons/s$

Explanation:

The radiated power can be given in terms of the wavelength as follows:

$Rasiated\ Power = \frac{nE}{t} = \frac{nhc}{\lambda t}$

where,

Radiated Power = 1.2 x 10⁻¹⁷ W

n = no. of photons = ?

h = plank's constant = 6.625 x 10⁻³⁴ J.s

c = speed of light = 3 x 10⁸ m/s

λ = wavelength = 500 nm = 5 x 10⁻⁷ m

t = time

Therefore,

$1.2\ x\ 10^{-17}\ W = \frac{n(6.625\ x\ 10^{-34}\ J.s)(3\ x\ 10^8\ m/s)}{(5\ x\ 10^{-7}\ m)(t) }\\\\\frac{n}{t} = \frac{1.2\ x\ 10^{-17}\ W}{3.975\ x\ 10^{-19}\ J}\\\\\frac{n}{t} = 30\ photons/s$

8 0

2 years ago