7.5 x 10⁻¹¹m. An electromagnetic wave of frecuency 4.0 x 10¹⁸Hz has a wavelength of 7.5 x 10⁻¹¹m.
Wavelength is the distance traveled by a periodic disturbance that propagates through a medium in a certain time interval. The wavelength, also known as the space period, is the inverse of the frequency. The wavelength is usually represented by the Greek letter λ.
λ = v/f. Where v is the speed of propagation of the wave, and "f" is the frequency.
An electromagnetic wave has a frecuency of 4.0 x 10 ¹⁸Hz and the speed of light is 3.0 x 10⁸ m/s. So:
λ = (3.0 x 10⁸ m/s)/(4.0 x 10¹⁸ Hz)
λ = 7.5 x 10⁻¹¹m
The appropriate expression for the calculation of power by relating the angular energy in a given time.
In other words the instantaneous power of an angular accelerating body is the torque times the angular velocity
Where
Torque
Angular speed
Our values are given by
The angular velocity must be transformed into radians per second then
Replacing,
The average power delivered by the engine at this rotation rate is 211.1kW
Answer: 10Nm or 10J
Explanation:
Given the following :
Force (f) = 5
Distance (d) = 2m
Calculate the kinetic energy assuming no friction
Work done = force × distance
Work done = 5N × 2m = 10Nm
Recall :
Work done = ΔK.E ( change in kinetic energy)
Therefore, kinetic energy of the book after sliding = ΔK. E, which is equal to work done.
Hence, K. E of book after sliding is 10Nm
Part A. For this part, we use two equations for linear
motion:
<span>y = y0 + v0 t + 0.5 g t^2 --->
1</span>
<span>vf = v0 + g t --->
2</span>
First we solve for t using equation 1: y0 = 0 (initial
point at top), y = 250 m, v0 = 0 (at rest)
250 = 0.5 (9.8) t^2
t = 7.143 s
Now we solve for final velocity vf using equation 2:
vf = g t
vf = 9.8 (7.143)
vf = 70 m/s
Part B. First we solve for the time it takes for the sound
to reach the tourist.
t(sound) = 250 / 335 = 0.746 s
Therefore the total time would be:
t = 0.746 s + 0.300 s
t = 1.05 s
<span>Hence there is enough time for the tourist to get out
before the boulder hits him.</span>
