Answer:
Inside the film the wavelength will be λ/n
For constructive interference to occur the film must be λf/4 thick where λf is the wavelength of the light in the film - there will be a 180 degree phase shift at the water/film interface since the index of refraction of the film is greater than that of water - and the light has to travel λ/2 inside the film for constructive interference to occur
280 nm / 1.6 * 4 = 700 nm is the greatest wavelength allowed
Note that 700 nm is also the upper wavelength of the visible spectrum
Answer:
a. Mass flow rate through the boiler = 5.462lbm/s
b. Power produced by the turbine = 2525.8kW
c. The rate of heat supply in the boiler = 6901.42Btu/s
d. Thermal efficiency of the cycle = 34.3%
Explanation:
In order to provide a solution, we must assume that ;
- The system is operating at a steady condition
- Kinetic and potential energy changes are negligible
Now from steam tables, we calculate specific volume 
and enthalpy 
as,
( 
at 
)
( 
at )
( at 
& 
)
( 
& 
when pressure is 2psia)
Therefore,
To calculate the mass flow rate of steam in the cycle, we use the formula
where 
The power output and the rate of heat addition are calculated thus,
The thermal efficiency of the cycle can be found thus;
= 34.3%
Answer:
4m/s
Explanation:
The motion is in downward direction, and the boat is moving with constant velocity, the position of the boat horizontally is 12m before the key fall.
The height difference "h"= ( y- y°)= 45 m
We can determine the needed time the key requires to reach the water using the expression from Newton's law
h= v(o) + 1/2 at^2
g= acceleration due to gravity= 9.8m/s^2
h= v(o) + 1/2 gt^2 -------------------------eqn*)
V(o)= 0 for the key= initial velocity
h= height that the key falls= 45m
If we substitute the above values into eqn(*) we have
We can make t^2 subject of the formula since v(0)= 0
t^2= h/(1/2 g)
= 45/(1/2× 9.8)
t^2= 45/4.9=9.18
t= √9.18
t=3.03 secs
Since the boat was moving with constant velocity,
Then Velocity= distance/ time
= 12/3.03
Velocity= 4m/s
Hence, the speed of the boat is 4m/s
Answer:d
Explanation:
It is good to extend your bare hand forward when you are getting ready to catch a fast-moving ball so you can pull your hand back, increasing the time to slow the ball thus decreasing the force.
While catching impulse is being transferred to hands imparting great force, lowering hand would increase the time so that average force decreases and chances to drop the ball also decreases.
Inertia is the tendency of an object to resist a change in its motion.
