This is another one of those muddy misleading questions, followed by
a muddy group of choices from which an answer must be selected.
a). is absurd. There's no such thing as a "balanced force", only
a balanced group of forces.
b). is probably the choice the question is aiming for.
c). is not so. The engines of an airplane do plenty of work lifting the plane
off the ground, although the force of the engines is never directed upward.
d). is really awkward. The object's motion is almost never the cause of the force.
The force is almost always the cause of the object's motion.
Now for the big 800-lb gorilla in the room: No moving object needs to be involved
in order for energy to be flowing or work to be getting done.
-- A radio wave radiates through space. Straighten out a wire coat-hanger and
stick it up in the air where the radio wave can pass by it. Electrical current flows
through the wire, and you can drain the electrical energy out the bottom of it.
-- A light bulb is shining. Some distance away, something it's shining on
gets warm, because of the heat energy that has shot across to it from the
light bulb and soaked into it.
-- A lightning bolt jumps from the ground to a passing cloud. Or, if you feel
more comfortable with it, a lightning bolt jumps from a cloud to the ground.
It doesn't matter. Either way, there's enough energy splashing around to
ignite houses, zap TVs and computers, melt concrete, vaporize water, and
light up a city. Although nothing is moving.
Answer:
a.Internal temperature change is 90.49°F
b.Internal energy change is -2.43Btu/lbm
Explanation:
The energy balance for this steady-flow system can be expressed as:
Therefore,
#Since:
From tableA-1
#Replacing the values in the equation:
We have that
Answer:
497.143 nm.
Explanation:
Diffraction grating experiment is actually done by passing light through diffraction glasses, the passage of the light causes some patterns which can be seen on the screen. This is because light is a wave and it can spread.
The solution to the question is through the use of the formula in the equation (1) below;
Sin θ = m × λ. ---------------------------------(1).
Where m takes values from 0, 1, 2, ...(that is the diffraction grating principal maxima).
Also, m × λ = dc/ B -------------------------------------------(2).
We are to find the second wavelength, therefore;
λ2 =( m1/c1) × (c2/m2) × λ1 ------------------------(3).
Where c1 and c2 are the order maximum and m = order numbers. Hence;
λ2 = (1/ .350) × (.870/3) × 600 = 497.143 nm.
Answer:
(a) Angular speed of resultant combination will be rev/min
(b) Fraction of total energy loss will be 0.9
Explanation:
We have given angular speed of the first wheel
According to question moment of inertia of second wheel is 9 times the moment of inertia of first wheel
So
(a) Now according to law of conservation of angular momentum
(b) Change in rotational kinetic energy will be equal to .......eqn1
Putting these values in eqn 1
Change in kinetic energy will be 0.9