PLEASE help me with this science question.

Question 3

Yuki888 [10]

Answer:

$Power = 2.5kW$

Explanation:

Given

$Mass = 200kg$ -- mass of tub

$Energy = 200,000J$

$Time = 80s$

Required

Determine the amount of power needed

Power is calculated as thus:

$Power = \frac{Energy}{Time}$

Substitute values for Energy and Time

$Power = \frac{200,000J}{80s}$

$Power = 2500W$

Divide by 1000 to convert to kW (kilowatt)

$Power = 2.5kW$

4 0

2 years ago

A soap bubble is essentially a thin film of water surrounded by air. the colors you see in soap bubbles are produced by interfer

scoray [572]

The colors we see in the bubble are produced by the interference between two waves: a) the wave reflected by the surface of the bubble b) the wave that travels inside the bubble and it is reflected by its back.
The condition for the constructive interference is that the phase shift between the two waves is an integer multiple of $2\pi$ . The phase difference between the two waves is
$\Delta \phi = k \Delta x - \pi$
where $\Delta x = 2t$ is twice the thickness of the bubble (since the second wave travels inside the bubble and it is reflected from the back), while $\pi$ is due to the fact that the first wave has an extra phase shift $\pi$ because it is reflected from a material (soap) with higher refraction index than the air.

So, in order to have constructive interference, we should require
$k \Delta x - \pi = 2m\pi$
where m is an integer. Substituting $\Delta x=2t$ and $k= \frac{2 \pi}{\lambda}$ , we have
$\lambda = \frac{2t}{m+ \frac{1}{2} }$
But here $\lambda$ is the wavelength in the soap; we need instead the wavelength in the air, which is
$\lambda' = n \lambda$
where n=1.33 is the refraction index.

Therefore, we have
$\lambda' = \frac{2nt}{m+ \frac{1}{2} }$

Using t=390 nm, and using different values of m, we find tha only m=1 and m=2 have wavelength in the visible spectrum: $\lambda'=415 nm$ and $\lambda'=692nm$ . These wavelengths correspond to red and violet, so the bubble appears as red-violet.

4 0

3 years ago

Read 2 more answers

Kayla drew a diagram to compare convex and concave lenses which labels belong in the areas marked XYZ

lesya692 [45]

Answer:

X: Causes light rays to bend toward the principal axis

Y: Is capable of producing images that are smaller than objects

Z: Causes light rays to bend away from the principal axis

Explanation:

just took the test...

8 0

3 years ago

A 20 kg wagon is pulled along the level ground by a rope inclined at 30 degree above the horizontal. A friction force of 30 N op

Elan Coil [88]

(a) 34.6 N

To solve the problem, we have to analyze the forces acting along the horizontal direction.

We have:

- Forward: the component of the pull parallel to the ground, which is

$F cos \theta$

where

F is the magnitude of the pull

$\theta=30^{\circ}$ is the angle

- Backward: the force of friction, which is

$F_f = 30 N$

So, the equation of motion is

$F cos \theta - F_f = ma$

where

m = 20 kg is the mass of the wagon

a is the acceleration

In this part, the wagon is moving at constant speed, so a =0 and the equation becomes

$F cos \theta - F_f = 0$

Therefore, we can find the pulling force:

$F=\frac{F_f}{cos \theta}=\frac{30}{cos 30}=34.6 N$

(b) 43.9 N

In this case, the acceleration is

$a=0.40 m/s^2$

So, the equation of motion in this case is

$F cos \theta - F_f = ma$

So this time we have to take into account the term (ma).

Using the same data as before:

m = 20 kg

$\theta=30^{\circ}$

$F_f = 30 N$

We find the new magnitude of F:

$F=\frac{ma+F_f}{cos \theta}=\frac{(20)(0.40)+30}{cos 30}=43.9 N$

6 0

3 years ago

The vibrations produced by a jackhammer are used to break up pavement. What type of waves did/does the jackhammer produce into t

klio [65]

<span>P waves

P-waves are sometimes called pressure waves, and sometimes they are called longitudinal waves. P-waves are transmitted through the Earth’s interior with a backwards and forwards motion along the line of travel, by alternating compression and dilatation. A jack hammer creates P-waves. They are capable of passing through any type of material they encounter, including the liquid of the Earth’s outer core, although they
will be bent and deflected when they pass across the boundaries separating
layers of different densities.

I hope my answer has come to your help. Thank you for posting your question here in Brainly. We hope to answer more of your questions and inquiries soon. Have a nice day ahead!
</span>

8 0

3 years ago