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telo118 [61]
3 years ago
13

A laser produces 20.0 mW of red light. In 1 hour, the laser emits 2.29 X 10^20 photons. What is the wavelength of the laser?

Physics
1 answer:
Butoxors [25]3 years ago
8 0
Using Planck's equation,

E = nhc / λ

Also, Power = Energy / time
E = 20 x 10⁻³ x 60 x 60
E = 108 J

108 = (2.29 x 10²⁰ x 6.63 x 10⁻³⁴ x 3 x 10⁸) / λ
λ = 4.22 x 10⁻⁷ m
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A person spins a tennis ball on a string in a horizontal circle (so that the axis of rotation is vertical). At the point indicat
Ilya [14]

Answer:

direction does the axis of rotation tilt toward after the blow is the z- direction

Explanation:

This is because

Due to the blow, there is a impulse imparted on the ball which gives a change in linear momentum () in the x direction

Thus When cross product of momentum in x direction is taking with r vector, we will get resultant in z direction. Hence change in angular momentum will be z direction.

5 0
3 years ago
What is the tangential velocity of a record player which makes 11 revolutions in 20 seconds?
slava [35]

Answer:

The tangential velocity of a rotating object is:

v = r*w

where r is the radius, and w is the angular velocity.

w = 2*pi*f

where f is the frequency.

We know that the record plater does 11 revolutions in 20 seconds, then it does:

11 rev/20s = 0.55 rev/s = f

then we have:

w = 2*pi*0.55 s^-1 = 2*3.14*0.55 s^-1 = 3.454 s^-1

The radius of a record player is really variable, it is around 10 inches, so i will use r = 10in, which is the rotating part of the record player.

then the tangential velocity is:

v = 10in*3.454 s^-1 = 34.54 in/s

7 0
3 years ago
Strong winds causing a vehicle to lose all control is called
mixer [17]
The answer to this question is "Buffeting". This is an unusual strong wind condition that resulted in the loss of vehicle control. This condition occurs in roads and bridges, across and along mountains that affected vehicles control. The drivers must be alert and put their full attention to overcome this condition.
4 0
3 years ago
Q1. Tractors are often used on sloping fields, so stability is important in their design. On the diagram, the center of the X ma
Vesna [10]

Answer:

a) The tractor has not toppled over because the the center of mass is acting in between the wheels

b) The features which affect its stability are;

1) The location of the center of gravity of the tractor close to the ground

2) The increased spacing between the left and the right wheels of the tractor

Q2. a) The center of mass wheel act in the region to the right away the wheel span (space in between the wheel) which creates a clockwise effect to, topple the buses over

b) It raises the bus's center of mass higher

c) To raise the center of mass to its highest practical level

Q3. At the bottom middle location within the tractor

Explanation:

a) The tractor has not toppled over because the vertical line from the center of gravity to the ground is still in between the wheel base such that since the tractor will topple over by turning clockwise about the right tire due to its weight, the weight of the tractor is currently acting in the anticlockwise direction to the right end tire of the tractor keeping the tractor's tires in good contact with the ground

b) The features which affect its stability are;

1) The location of the center of gravity of the tractor close to the ground

2) The increased spacing between the left and the right wheels of the tractor

Q2. a) When either of the buses are tilted further, the mass of the buses is acting on the tires and in their tilted condition, the mass is acting mainly on the right tire, whereby as the vertical line from the center of mass to the ground is in between the wheel bases the mass of the buses still serve s the restoring force to keep the bus on ground by providing anticlockwise moment where clockwise lotion is required for the bus to topple over

If the buses are tilted further, the vertical line from the center of mass will cross to the other side of the right tire such that the mass now provides clockwise moment turning the buses clockwise and since there are no opposing anticlockwise moment to balance that of the now clockwise moment of the buses it will continue to turn clockwise with the result that they eventually  topple over

b) When the upper deck is full of passengers, there will be an appreciable proportion of the total mass of the bus in the upper deck such that the level of the center of mass will be raised up higher

c) Sand bags are only put upstairs because by allowing for the disproportionate distribution of load such that the majority of the load of the bus is concentrated upstairs, the center of mass will be at its maximum height allowing the bus to be tested for stability in the worst case scenario

Therefore, the sands are only put upstairs to raise the center of mass

Q3. Being that the tractor is being used on a rough ground, the safest position will be at the lowest possible location at the middle of both the front and rear wheels and the left and right tires.

5 0
3 years ago
An experiment is performed in the lab, where the mass and the volume of an object are measured to determine its density. Two com
navik [9.2K]

Answer:

d. the same within the uncertainty of each measurement method

Explanation:

The density of an object and in general any physical property, has the same value regardless of the method used to measure it, either directly or indirectly. Since two completely different valid methods are used, the results must be the same, taking into account the level of precision of each of the methods.

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3 years ago
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