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Citrus2011 [14]
4 years ago
10

While running a 100m race, a runner runs from the 20m to 30m mark in 77 frames of a video record. If the video camera recorded d

ata at 50 frames/s, how fast was she running during the video interval (in m/s)
Physics
1 answer:
Marrrta [24]4 years ago
3 0

Answer:

Speed of the runner during video interval is 6.49 m/s

Explanation:

According to the problem,

Number of frames recorded by camera in 1 second = 50

Time takes by camera to record 1 frame = (1/50) s

Time taken by camera to record 77 frames, t = \frac{1}{50}\times 77 s

Distance covered by the runner during the video recording, d = 10 m

Speed, v = \frac{Distance}{time}=\frac{d}{t}

Substitute the values of d and t in the above equation.

v = \frac{10}{\frac{77}{50} }

v = 6.49 m/s

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If we had a wave period of 0.0003 seconds what what would be its frequency?
yawa3891 [41]

Answer:

3,333.33 /sec

Explanation:

frequency = 1/period

= 1/0.0003 = 3,333.33 /sec

4 0
3 years ago
Help with these questions please?
iren2701 [21]

Three

The ray of light will come out of the glass at 90 degrees to the normal. What goes in is called the critical angle. At 90 degrees the ray will reflect rather than refract. This is just for interest.

<em><u>Formula</u></em>

n2 * sin(θ2) = n1* sin(θ1)

<em><u>Givens</u></em>

θ2 = 90 degrees

n2 = 1

n1 = ?

θ1 = 43.6

<em><u>Solution</u></em>

n1 * sin(43.6) = 1 * 1

n1 = 1/sin(43.6)

n1 = 1/0.6896

n1 = 1.45

Four

This problem is very instructive. It uses a little known trick so that you don't have to know the exact speed of light of one of the speeds. The other speed is compared to it. You could do it the long way and figure out the speeds in crown glass from air to the crown glass, and do the same thing with the other color. That would work. An easier way is not to bother. Call the speed of one of the colors = 1. Is the other speed greater or less than 1? We'll see.

The next thing you have to realize is that the speed is going to be  highest for either red or violet. That's because n is highest for violet and lowest for red. The intermediate colors don't matter. So the answer is either A or B.

They have n's between violet and red and so they will not be an answer. That means you can eliminate green and yellow (answers C and D).

<em><u>Formula</u></em>

v1/v2 = n2/n1

<em><u>Givens</u></em>

v1 = 1 (we'll say this is red)

v2 = ? (this is violet)

n2 = 1.62 for red. This is probably not exact, but it does not have to be. You just have to notice that violet is higher

n1 = 1.65 for violet. So you are trying to solve the relative speed of v2.

<em><u>Solution</u></em>

v1/v2 = n2/n1

1/v2 = 1.65/1.62      Cross multiply

1.65 * v2 = 1 * 1.62  Divide by 1.65

v2 = 1.62/1.65

v2 = 0.98

<em><u>Conclusion</u></em>.

The speed of violet is going to be slower than the speed of red.

Rule: the higher the index of refraction, the lower the speed.

Answer: red has the greater speed.

5 0
3 years ago
an electron does not suffer any deflection through a region of uniform magnetic field. What is direction of magnetic field?​
a_sh-v [17]

Explanation:

An electron does not suffer any deflection while passing through a region of uniform magnetic field. What is the direction of the magnetic field ? Solution : The direction of magnetic field B is parallel or antiparallel to the velocity →V of electron.

7 0
3 years ago
How many miles of MgCI2 are there in 339g of compound?
harkovskaia [24]

I'm going to answer this by using rounded numbers for the atomic masses. You need only go back and put the numbers in from your periodic table. My answers will be close, but not what you should get.

Find the Molar Mass of MgCl2

Mg =                   24 grams

2Cl = 2 * 35.5 = 71 grams

Total  =              95 grams

Find the mols in 339 grams

1 mole = 95 grams

x mol = 339

Solve

339 = 95x   Divide by 95

339/95 = x

x = 3.67 mols  Answer

4 0
3 years ago
10) What is the total energy of a 450-g mass that is attached to a horizontal spring with a force constant of 260 N/m and oscill
VikaD [51]

Answer:

E = 1/2 * k x^2 is the energy stored in the spring

E = 1/2 * 260 N/m * .08^2 m = .832 Joules

8 0
2 years ago
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