-- The energy of one photon is <em>(h · frequency of the light)</em>
' h ' is 6.626 × 10⁻³⁴ m²-kg/s ("Planck's Constant")
-- The question doesn't tell you the frequency of the light from the LED, but it tells you the wavelength, and
<em>Frequency = (speed of light) / (wavelength) </em>.
-- Now you have everything you need to calculate the <em>energy carried by one photon from the LED</em>.
-- The power of the light from the LED is 120 milliwatts. That's <em>0.120 Joule of energy per second</em>.
Now you should be able to find the number of photons per second. It's going to be <em>(0.120 Joule) / (energy carried by one photon)</em> .
When I scribbled it out on a scrap of scratch paper, I got 3.853 x 10³⁸ photons, but you'd better really check that out.
9 Newtons on the right, because:
Right and left are opposite directions, however, in the same direction.
We know that, opposite directions, the signal is of subtraction. So, you need to make the difference between 22 and 13, you will see that it is 9. Therefore, the Resulting Force will be 9.
Answer:
v<em>min</em> = 0.23 m/s
Explanation:
The golf ball must travel a distance equal to its diameter in the time between blade arrivals to avoid being hit. If there are 12 blades and 12 blade openings and they have the same width, then each blade or opening is 1/24 of a circle of is 2π/24 = 0.26 radians across.
Therefore, the time between the edge of one blade moving out of the way and the next blade moving in the way is
time = angular distance/angular velocity
⇒ t = 0.26 rad / 1.35 rad/s = 0.194 s
The golf ball must get completely through the blade path in this time, so must move a distance equal to its diameter in 0.194 s, therefore the speed of the golf ball is
v =d/t
⇒ v = 0.045 m / 0.194 s = 0.23 m/s
Answer:
d. None of the above.
Explanation:
In a parabolic motion, you have that in the complete trajectory the component velocity is constant and the vertical component changes in time. Then, the total velocity vector is not zero.
In the complete trajectory the gravitational acceleration is always present. Then, the grasshopper's acceleration vector is not zero.
At the top of the arc the grasshopper is not at equilibrium because the gravitational force is constantly acting on the grasshopper.
Then, the correct answer is:
d. None of the above.
