1.concave lens

Wave traveling at 330 m/sec has a wavelength of 4.3 meters. What is the frequency of this wave?

Rasek [7]

Answer:

76.74 Hz

Explanation:

Given:

Wave velocity ( v ) = 330 m / sec

wavelength ( λ ) = 4.3 m

We have to calculate Frequency ( f ):

We know:

v = λ / t [ f = 1 / t ]

v = λ f

= > f = v / λ

Putting values here we get:

= > f = 330 / 4.3 Hz

= > f = 3300 / 43 Hz

= > f = 76.74 Hz

Hence, frequency of sound is 76.74 Hz.

6 0

3 years ago

Which of the following best describes a galaxy?

valentinak56 [21]

Answer:

B-Large groups of stars held together by gravity

Explanation:

4 0

3 years ago

A ray of light incident in water strikes the surface separating water from air making an angle of 10 ° with the normal to the su

labwork [276]

Answer:

a

$\theta _2 = 13^o$

b

$\theta _1 =32.94^o$

c

$\theta_c = 53.05^o$

Explanation:

From the question we are told that

The angle of incidence is $\theta_1 = 10^o$

The refractive index of water is $n_1 = 1.3$

Generally Snell's law is mathematically represented as

$n_1 sin(\theta_1) = n_2 sin(\theta_ 2)$

Here $n_2$ is the refractive index of air with value $n_2 = 1$

$\theta_2$ is the angle of refraction

So

$\theta _2 = sin^{-1}[\frac{n_1 * sin(\theta _1)}{n_2} ]$

=> $\theta _2 = sin^{-1}[\frac{1.3 * sin(10)}{1} ]$

=> $\theta _2 = 13^o$

Given that the angle should not be greater than $\theta _2 =45^o$ then the angle of incidence will be

$\theta _1 = sin^{-1}[\frac{n_2 * sin(\theta _2)}{n_1} ]$

=> $\theta _1 = sin^{-1}[\frac{1 * sin(45)}{1.3} ]$

=> $\theta _1 =32.94^o$

Generally for critical angle is mathematically represented as

$\theta_c = sin^{-1}[\frac{n_2}{n_1} ]$

=> $\theta_c = sin^{-1}[\frac{1}{1.3} ]$

=> $\theta_c = 53.05^o$

4 0

3 years ago

PLEASE HELP ASAP!!! CORRECT ANSWER ONLY PLEASE!!!

Sonbull [250]

Question 1

In order to do work, the force vector must be

in the same direction as the displacement vector and the motion.

Question 2

In which of the following cases is work being done on an object?

Pulling a trailer up a hill

Question 3

Which situation is an example of NOT doing work?

carrying a box

Question 4

Work is measured in

Joules

Question 5

To find the work done, the force exerted and distance moved are multiplied. A couch is moved twice before you are happy with its placement. The same force was used to move the couch both times. If more work is done the first time it is moved, what do you know about the distance it was moved?

When more work was done, the couch was moved further.

Question 6

A weight lifter raises a 1600 N barbell to a height of 2.0 meters. How much work was done? W = Fd

3200 Joules

Question 7

You and a friend (Alex) are at a a tree-top adventure park .. . . part of the course requires you to climb up a rope. You both climb the same rope in the same amount of time. However, the tension in the rope is greater

when Alex climbs. Who did the most work?

Alex did - more tension means more force - more force means more work was done

Question 8

Doing work at a faster rate creates power.

more

Question 9

In one challenge on the Titan Games, competitors have to lift 200 pounds up a long ramp. Angel is able to move the weight in 42 seconds. Anthony gets it done in only 38 seconds. Which statement is true?

Anthony has more power than Angel.

Question 10

A mountain climber exerts 41,000 J of work to climb a cliff. How much power does the climber need if she wants to finish in only 500 seconds? Power = Work / time

82 Watts

Question 11

Your family is moving to a new apartment. While lifting a box 83 Joules of work is done to put the box on a truck, you exert an upward force of 75 N for 3 s. How much power is required to do this? (Hint: You only need two of the 3 numbers given!) Power = Work / time

27.7 Watts

*100% CORRECT ANSWERS

4 0

3 years ago

A diver running 2.5 m/s dives out horizontally from the edge of a vertical cliff and 3.0 s later reaches the water below. how hi

Elodia [21]

Answer:

a) Height of cliff = 44.145 meter

b) 7.5 meter far from its base the diver hit the water.

Explanation:

We have equation of motion , $s= ut+\frac{1}{2} at^2$ , s is the displacement, u is the initial velocity, a is the acceleration and t is the time.