For a photographer that wishes to determine the color of light that he can use in a dark room that will not expose the films he is processing, having used a Blue Incandescent bulb, he should proceed to use a Red Incandescent bulb for the next trial.
The photographer in question is performing an experiment. For these kinds of experiments it is important to identify the variables present, which can be of three kinds:
- Control variables
- Dependent variables
- Independent variables
For this experiment, the dependent variable is the exposure of the light onto the films, given that this is what we wish to measure. The independent variable will be the color of the light being used which is what will affect the dependent variable.
The remaining variable must be the control variable. Unlike the previous variables, we can have more than one of these. The control variable is there to make sure that only the dependent variable is affecting the outcome. We do this by keeping the control variable the same through each trial, which is why the photographer should not change the type of bulb in the second experiment, changing only the color of the light.
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Answer:
Part a)

Part b)

Part c)

Explanation:
Part a)
As we know that the friction force on two boxes is given as



Now we know by Newton's II law

so we have




Part b)
For block B we know that net force on it will push it forward with same acceleration so we have




Part c)
If Alex push from other side then also the acceleration will be same
So for box B we can say that Net force is given as




Answer:

Explanation:
Newton's 2nd law is given as
.
To find the acceleration in the horizontal direction, you need the horizontal component of the force being applied.
Using trigonometry to find the horizontal component of the force:

Use this horizontal component of the force to solve for for the acceleration of the object:

Answer:
-The speed of sound at 33°C is 362.8 m/s.
-The wavelength at a frequency at 5 kHz is 0.07256 m .
Explanation:
let v = 343 m/s be the speed of sound.
let T be the temperature.
then the speed of sound V, at 33°C is given by:
V = v + 0.6×T
= 343 + 0.6×33
= 362.8 m/s
Therefore, the speed of sound at 33°C is 362.8 m/s.
the wavelength at a frequency of f = 5kHz = 5000 Hz is given by:
λ = V/f
= (362.8)/(5000)
= 0.07256 m
Therefore, the wavelength at a frequency at 5 kHz is 0.07256 m .
Answer:
b bc they are a dangerous threat to humans health