Given:
distance from the projector lens to the image, di
projector lens focal length, f
distance from the transparency to the projector lens, do
thin lens equation: 1/f = 1/di + 1/do
do = 4 inches
di = 8 feet
convert feet to inches, for uniformity.
1 foot = 12 inches
8 feet * 12 inches/ft = 96 inches
1/f = 1/96 inches + 1/4 inches
Adding fractions, denominator must be the same.
1/f = (1/96 * 1/1) + (1/4 * 24/24)
1/f = 1/96 + 24/96
1/f = 25/96
to find the value of f, do cross multiplication
1*96 = f * 25
96 = 25f
96/25 = f
3.84 = f
The focal length of the project lens is 3.84 inches
The Doppler Effect provides the equation for the
calculation of apparent frequency:
f=fo[vo/(vo-vr)]
where:<span>
vo=source wave velocity
vr=relative speed between source and observer
f=apparent frequency
fo=source frequency </span>
<span>
The velocity of the doppler wave is
v=λf</span>
where λ is light wavelength. Hence,
v=λfo[vo/(vo-vr)]
Based on the equation, we can say that wave
velocity will always be defined by one and only one wavelength.
Therefore the answer is letter C.
<span> </span>
Given :
Initial speed of car A is 15 m/s and initial speed of car B is zero.
Final speed of car A is zero and final speed of car B is 10 m/s.
To Find :
What fraction of the initial kinetic energy is lost in the collision.
Solution :
Initial kinetic energy is :
Final kinetic energy is :
Now, fraction of initial kinetic energy loss is :
Therefore, fraction of initial kinetic energy loss in the collision is 1.25 .
Example of surface events are erosion and weathering. Erosion is the carrying of a particle from one place to the other and weathering is the breaking down of particles. These processes help in rock formation because this allows physical changes (grouping together or breaking down) on a certain substance. Subsurface events are those which happened underground such as the flow of underground water which subsequently allow the deposition of minerals, etc.
