What is the number of waves per second in a radio signal?

A projectile is launched straight up from a height of 960 feet with an initial velocity of 64 ft/sec. Its height at time t is h(

Natasha2012 [34]

Answer:

a) $t=2s$

b) $h_{max}=1024ft$

c) $v_{y}=-256ft/s$

Explanation:

From the exercise we know the initial velocity of the projectile and its initial height

$v_{y}=64ft/s\\h_{o}=960ft\\g=-32ft/s^2$

To find what time does it take to reach maximum height we need to find how high will it go

b) We can calculate its initial height using the following formula

Knowing that its velocity is zero at its maximum height

$v_{y}^{2}=v_{o}^{2}+2g(y-y_{o})$

$0=(64ft/s)^2-2(32ft/s^2)(y-960ft)$

$y=\frac{-(64ft/s)^2-2(32ft/s^2)(960ft)}{-2(32ft/s^2)}=1024ft$

So, the projectile goes 1024 ft high

a) From the equation of height we calculate how long does it take to reach maximum point

$h=-16t^2+64t+960$

$1024=-16t^2+64t+960$

$0=-16t^2+64t-64$

Solving the quadratic equation

$t=\frac{-b±\sqrt{b^{2}-4ac}}{2a}$

$a=-16\\b=64\\c=-64$

$t=2s$

So, the projectile reach maximum point at t=2s

c) We can calculate the final velocity by using the following formula:

$v_{y}^{2}=v_{o}^{2}+2g(y-y_{o})$

$v_{y}=±\sqrt{(64ft/s)^{2}-2(32ft/s^2)(-960ft)}=±256ft/s$

Since the projectile is going down the velocity at the instant it reaches the ground is:

$v=-256ft/s$

5 0

2 years ago

Based on Newton’s 3rd Law of motion, if an archer shoots an arrow at the target, the action force is the bowstring against the a

maw [93]

Answer:

maybe target, not sure.

6 0

2 years ago

2. A 1.30-m long gas column that is open at one end and closed at the other end has a fundamental resonant frequency 80.0 Hz. Wh

Elina [12.6K]

To solve this problem, it will be necessary to apply the concepts related to the fundamental resonance frequency in a closed organ pipe.

This is mathematically given as

$f_n (2n+1)(\frac{v}{4L})$

For fundamental frequency n is 0, then,

$f_0 = \frac{v}{4L}$

When,

v = Velocity of sound

L = Length,

Rearranging to find the velocity,

$v = f_0 (4L)$

$v = (80Hz)(4)(1.3m)$

$v = 416m/s$

Therefore the speed of sound in this gas is 416m/s

7 0

3 years ago

Waves diffract the most when their wavelength is

djverab [1.8K]

<h2>Answer: about the same size of the gap or slit</h2>

Diffraction happens when a wave (mechanical or electromagnetic wave, in fact, any wave) meets an obstacle or a slit .When this occurs, the wave bends around the corners of the obstacle or passes through the opening of the slit that acts as an obstacle, forming multiple patterns with the shape of the aperture of the slit.

Note that the principal condition for the occurrence of this phenomena is that the obstacle must be comparable in size (similar size) to the size of the wavelength.

In other words, when the gap (or slit) size is larger than the wavelength, the wave passes through the gap and does not spread out much on the other side, but when the gap size is equal to the wavelength, maximum diffraction occurs.

Therefore:

<h2>Waves diffract the most when their wavelength is <u>about the same size of the gap </u></h2>

<u />

5 0

2 years ago

Which of the following statements are correct? 1. Electrons and protons have identical masses but opposite charges. 2. Most of a

lisabon 2012 [21]

Answer:

b 2 only

Explanation:

The mass of an electron is 9.10938356 × 10⁻³¹ kilograms while the mass of a proton is 1.6726219 × 10⁻²⁷ kilograms. It can be seen that a proton is heavier than an electron.

Atoms do not always have the same number of neutrons and protons. For, example ¹³C has 6 protons and 7 neutrons.

Atoms do have most of the mass concentrated at the center called the nucleus. The nucleus has protons and neutrons. As protons have positive charge and neutrons have no charge the nucleus has a positive charge.

7 0

2 years ago