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3 years ago

Longitudinal waves cannot travel through a vacuum. True False

1 answer:

4 0

FALSE Only electromagnetic waves can travel through a vacuum; mechanical waves such as sound waves require a particle-interaction to transport their energy. There are no particles in a vacuum. Waves are either longitudinal or transverse.
Hoped i helped :):)

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Calculate the speed of the ball, vo in m/s, just after the launch. A bowling ball of mass m = 1.5 kg is launched from a spring c

klemol [59]

Answer:

$v_0=17.3m/s$

Explanation:

In this problem we have three important moments; the instant in which the ball is released (1), the instant in which the ball starts to fly freely (2) and the instant in which has its maximum height (3). From the conservation of mechanical energy, the total energy in each moment has to be the same. In (1), it is only elastic potential energy; in (2) and (3) are both gravitational potential energy and kinetic energy. Writing this and substituting by known values, we obtain:

$E_1=E_2=E_3\\\\U_e_1=U_g_2+K_2=U_g_3+K_3\\\\\frac{1}{2}kd^2=mg(d\sin\theta)+\frac{1}{2}mv_0^2=mgh+\frac{1}{2}m(v_0\cos\theta)^2$

Since we only care about the velocity $v_0$ , we can keep only the second and third parts of the equation and solve:

$mgd\sin\theta+\frac{1}{2}mv_0^2=mgh+\frac{1}{2}mv_0^2\cos^2\theta\\\\\frac{1}{2}mv_0^2(1-\cos^2\theta)=mg(h-d\sin\theta)\\\\v_0=\sqrt{\frac{2g(h-d\sin\theta)}{1-\cos^2\theta}}\\\\v_0=\sqrt{\frac{2(9.8m/s^2)(4.4m-(0.21m)\sin32\°)}{1-\cos^232\°}}\\\\v_0=17.3m/s$

So, the speed of the ball just after the launch is 17.3m/s.

4 0

3 years ago

A simple harmonic oscillator of amplitude A has a total energy E.

jeka57 [31]

Answer:

a) $K=E-\frac{kA^2}{18}$

b) $U=\frac{kA^2}{18}$

Explanation:

The law of conservation of mechanical energy states that total mechanical energy remains constant during oscillation. Mechanical energy is defined as the sum of kinetic energy and potential energy:

$E=U+K\\E=\frac{kx^2}{2}+\frac{mv^2}{2}$

a) The position is one-third the amplitude. So, we have $x=\frac{1}{3}A$ . Replacing and solving for K

$E=\frac{k(\frac{1}{3}A)^2}{2}+K\\E=\frac{kA^2}{18}+K\\K=E-\frac{kA^2}{18}$

b) The potential energy is defined as:

$U=\frac{kx^2}{2}$

Replacing:

$U=\frac{k(\frac{1}{3}A)^2}{2}\\U=\frac{kA^2}{18}$

4 0

3 years ago

An amusement park ride consists of a rotating circular platform 11.1 m in diameter from which 10 kg seats are suspended at the e

frozen [14]

To solve this problem we will use the relationship given between the centripetal Force and the Force caused by the weight, with respect to the horizontal and vertical components of the total tension given.

The tension in the vertical plane will be equivalent to the centripetal force therefore

$Tsin\theta= \frac{mv^2}{r}$

Here,

m = mass

v = Velocity

r = Radius

The tension in the horizontal plane will be subject to the action of the weight, therefore

$Tcos\theta = mg$

Matching both expressions with respect to the tension we will have to

$T = \frac{\frac{mv^2}{r}}{sin\theta}$

$T = \frac{mg}{cos\theta}$

Then we have that,

$\frac{\frac{mv^2}{r}}{sin\theta} = \frac{mg}{cos\theta}$

$\frac{mv^2}{r} = mg tan\theta$

Rearranging to find the velocity we have that

$v = \sqrt{grTan\theta}$

The value of the angle is 14.5°, the acceleration (g) is 9.8m/s^2 and the radius is

$r = \frac{\text{diameter of rotational circular platform}}{2} + \text{length of chains}$

$r = \frac{11.1}{2}+2.41$

$r = 7.96m$

Replacing we have that

$v = \sqrt{(9.8)(7.96)tan(14.5\°)}$

$v = 4.492m/s$

Therefore the speed of each seat is 4.492m/s

6 0

4 years ago

Cardiorespiratory endurance involves these systems Group of answer choices A.Respiratory and digestive B.Digestive and circulato

yaroslaw [1]

C. Circulatory and respiratory

5 0

3 years ago

Define suspension and list two examples.

tigry1 [53]

Suspension, chemistry definition is a heterogenous mixture, meaning one substance is different from another, when mixed, either of the substance (particularly the solid one), do not mix evenly. It could clearly be seen when one mixes a solution in a suspension state because it forms a cloudy solution, Best example of this is mud. In mud, though there is a mixture of solid and liquid, there is still evident traces of solid particles that do not mix evenly in the solution.

3 0

3 years ago