Answer:
option A
Explanation:
given,
Force = F
angle = θ
weight on suitcase = mg
distance = d
constant velocity so, acceleration a = 0
coefficient of friction = µ
Work done = ?
Work done is equal to force into displacement.
Friction act opposite to the force acting so, work done by frictional force will be negative.
frictional force will act into horizontal direction opposite to force.
here displacement is equal to d
now,
W = -F d cos θ
Hence,the correct answer is option A
Answer:
that technician A is right
Explanation:
The test lights are generally small bulbs that are turned on by the voltage and current flowing through the circuit in analog circuits, these two values are high and can light the bulb. In digital circuits the current is very small in the order of milliamps, so there is not enough power to turn on these lights.
From the above it is seen that technician A is right
Answer:
The variation rate is 5.42 10⁻⁵ cm²/ºC
Explanation:
When we have a thermal expansion problem we must have the relationship of the change in length as a function of the temperature, which are given in this problem, so we can write the expression for the area of a rectangle
a = L W
They ask us to find the rate of variation of this area depending on the temperature, so we can derive this expression with respect to the temperature
da / dT = d(LW) / dt
We use the derivative of a product since the two magnitudes change
da / dT = W dL/dT + L dW/dT
The values they give us are
= 1.9 10⁻⁵ cm/ºC
= 8.5 10⁻⁶ cm/ºC
W = 1.6 cm
L= 2.8 cm
Substituting the values and calculating
= 1.6 1.9 10⁻⁵ + 2.8 8.5 10⁻⁶
= 3.04 10⁻⁵ + 2.38 10⁻⁵
= 5.42 10⁻⁵ cm²/ºC
The variation rate is 5.42 10⁻⁵ cm²/ºC
The wavelength of the emitted photon is(
)= 690nm
<h3>How can we calculate the wavelength of the emitted photon?</h3>
To calculate the wavelength of the photon we are using the formula,

Or,
We are given here,
= The energy difference between the two levels = 1. 8 ev=
C.
h= Planck constant =
Js.
c= speed of light =
m/s.
We have to find the wavelength of the emitted photon =
m.
Therefore, we substitute the known parameters in the above equation, we can find that,

Or,
Or,
m
Or,
=690 nm.
From the above calculation we can conclude that the wavelength of the emitted photon is 690nm.
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Answer:
∆p=(m2v)kg.m/s
Explanation:
∆p=mv where v=2v. hence ∆p=m2v