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3 years ago

.physics wave. Please don't dare to answer irrelevant

Physics

1 answer:

MAVERICK [17]3 years ago

3 0

Answer:

1a) 857143 m

1b) 414 m

2a)

2b)

3) the medium of air has a wavelength of 0.334 m, the medium of water has a wavelength of 1.493 m, and the medium of 5.130 m.

Explanation:

Question 1a)

Given the velocity/speed, and frequency of the wave, the length can be calculated using these two quantites.

[ λ = v / f ] wavelength = velocity of the wave / frequency of the wave in Hz.

Since 3 × 10^8 × ms^-1 is the velocity, and 350Hz is the frequency.

Anything to the negative power is reciprocated. i.e ms^-1 = m/s.

The wavelength is 300000000m/350Hz = 857142.8571428..... m ≈ 857143 m

Question 1b) Given that the frequency of the second wave in water is 1% of the first wave, and the speed of the second wave is 1450ms^-1

Therefore the second wave has a frequency of 1% of 3.5 = 350/100 Hz = 3.5 Hz

The wavelength is found using the same

formula: wavelength = 1450m/3.5Hz = 414.2857142857.... m ≈ 414 m

Question 2a)

Question 2b)

Question 3) Remember, the speed of sound of the medium = frequency of the medium × wavelength of the medium.

Therefore the wavelength of the medium = speed of sound of the medium / frequency of the medium. This has a similar correlation to the wavelength formula. We are given that all these mediums have a frequency of 1KHz = 1000Hz, where So the wavelength of each medium =

Question 4)

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A 2.7-kg block is released from rest and allowed to slide down a frictionless surface and into a spring. The far end of the spri

exis [7]

a) The speed of the block at a height of 0.25 m is 2.38 m/s

b) The compression of the spring is 0.25 m

c) The final height of the block is 0.54 m

Explanation:

We can solve the problem by using the law of conservation of energy. In fact, the total mechanical energy (sum of kinetic+gravitational potential energy) must be conserved in absence of friction. So we can write:

$U_i +K_i = U_f + K_f$

where

$U_i$ is the initial potential energy, at the top

$K_i$ is the initial kinetic energy, at the top

$U_f$ is the final potential energy, at halfway

$K_f$ is the final kinetic energy, at halfway

The equation can be rewritten as

$mgh_i + \frac{1}{2}mu^2 = mgh_f + \frac{1}{2}mv^2$

where:

m = 2.7 kg is the mass of the block

$g=9.8 m/s^2$ is the acceleration of gravity

$h_i = 0.54$ is the initial height

u = 0 is the initial speed

$h_f = 0.25 m$ is the final height of the block

v is the final speed when the block is at a height of 0.25 m

Solving for v,

$v=\sqrt{u^2+2g(h_i-h_f)}=\sqrt{0+2(9.8)(0.54-0.25)}=2.38 m/s$

The total mechanical energy of the block can be calculated from the initial conditions, and it is

$E=K_i + U_i = 0 + mgh_i = (2.7)(9.8)(0.54)=14.3 J$

At the bottom of the ramp, the gravitational potential energy has become zero (because the final heigth is zero), and all the energy has been converted into kinetic energy. However, then the block compresses the spring, and the maximum compression of the spring occurs when the block stops: at that moment, all the energy of the block has been converted into elastic potential energy of the spring. So we can write

$E=E_e = \frac{1}{2}kx^2$

where

k = 453 N/m is the spring constant

x is the compression of the spring

And solving for x, we find

$x=\sqrt{\frac{2E}{k}}=\sqrt{\frac{2(14.3)}{453}}=0.25 m$

If there is no friction acting on the block, we can apply again the law of conservation of energy. This time, the initial energy is the elastic potential energy stored in the spring:

$E=E_e = 14.3 J$