(d) What type of transformation is done by the following things?

A 13.0 g piece of Styrofoam carries a net charge of â5.40 Î¼C and floats above the center of a large horizontal sheet of plastic

kati45 [8]

Answer:

σ =4.180×10^{-9} C/m^2

Explanation:

electric field due to non conducting sheet is

$E=\frac{\sigma}{2\epsilon_0}$

the force acting on the piece of Styrofoam

Eq= mg

⇒E= mg/q

now,

$\frac{mg}{q} = \frac{\sigma}{2\epsilon_0}$

⇒ $\sigma= \frac{2mg\epsilon_0}{q}$

$\sigma= \frac{2\times0.013\times9.81\times8.85\times10^{-12}}{5.40\times10^{-4}}$

charge per unit area (in C/m2) on the plastic sheet σ =4.180×10^{-9} C/m^2

6 0

3 years ago

An athlete can twirl a baton so that it reaches an angular velocity of 12 rad/s from rest in 0.5 s. If the length of a uniform b

NikAS [45]

Answer:

The torque needed is 46.08 Nm

Explanation:

Given;

angular velocity, ω = 12 rad/s

time of motion, t = 0.5 s

length of the baton, r = 0.8 m

mass of the baton, 0.5 kg

The torque needed to reach the angular velocity is given by;

τ = F x r

where;

F is the centripetal force of the baton

r is the length of the baton = radius of the circular motion of the baton

$F_c =ma_c= \frac{mv^2}{r} = m\omega^2 r$

Torque is given by;

$\tau = F_c *r\\\\\tau = m \omega^2 r *r\\\\\tau = m \omega^2 r^2 \\\\\tau = (0.5)(12)^2(0.8)^2\\\\\tau = 46.08 \ N m$

Therefore, the torque needed is 46.08 Nm

6 0

3 years ago

Miss Piggy is exercising her vocal chords by matching the frequency f = 686 Hz of her speaker 4 m away. Where should Kermit sit

monitta

Answer:

$z=\frac{2n+1}{8}$ for $n=0,1,2,3,...,15$

Where z=0 m is the position of Miss Piggy and z=4 m is the position of the speaker.

Explanation:

Assuming that Miss Piggy emits a sound wave that is in phase with the speaker, and that z=0 is the position of Miss Piggy and z=4 is the position of the speaker, we would have a superposition of two traveling sound waves. Furthermore let's assume that both waves have the same amplitude. The total resulting wave will be given by:

$\psi(t,z)=A\cos(\omega t-kz)+A\cos(\omega t +kz)$ where $\omega$ is the angular frequency of the traveling wave and $k$ is the wave number defined as $k=\frac{2\pi}{\lambda}$ . $\lambda$ is the wavelength of both traveling waves (they have the same wavelength because they have the same frequency). $\lambda=\frac{v}{f}$ where v is the speed of sound.

By using the trigonometric identity $2\cos(A)\cos(B)=\cos(A+B)+\cos(A-B)$ we can rewrite $\psi (t,z)$ as

$\psi (t,z)=2A\cos(\omega t)\cos(kz)$ .

In order for the resulting wave to have maximum destructive interference, that is to be zero for any time t, we need to have

$\cos(kz)=0$

$\implies kz=(2n+1)\cdot \frac{\pi}{2}\implies z=(2n+1)\frac{\pi}{2k}=(2n+1)\frac{\pi}{2}\frac{\lambda}{2\pi}=(2n+1)\cdot \frac{\lambda}{4}$

$\implies z=(2n+1)\cdot\frac{v}{4f}=\frac{2n+1}{8}$

3 0

3 years ago

What are three sports that use force (EXCEPT FOOTBALL)

Anika [276]

Soccer, golf, baseball

6 0

3 years ago

A scientist watched a desert lizard stand in the rain. It spread its legs stretching its body wide, while holding its head and t

egoroff_w [7]

Answer:

Hypothesis:

When a scientist see lizard behaving in this way in each rainystrom in the desert, he can make a hypothesis about the lizard’s way of drinking water. He can say that lizard spread its legs to wide body. In this way it catches and carry water in microscopic channels on its body. These channels lead water to its mouth and it drinks this water by opening and closing mouth continuously.

3 0

3 years ago