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Rotation
Classical mechanics doesn't just describe how an object's position behaves under external influences, but also how its orientation behaves. Using the same principles found in Newtonian mechanics, laws and relations governing rotation can also be derived. Please direct all your questions about moments of inertia, angular velocity, angular momentum, centripetal force, centrifugal force, torque, and spin here.
645 Questions
Does the apparent focal spot size of a rotating anode tube depend upon the speed of anode rotation?
Yes, the apparent focal spot size of a rotating anode tube is affected by the speed of the anode rotation. A faster rotation speed can help reduce the effective focal spot size, leading to improved image resolution.
What is the Amplitude of a signal measure?
The amplitude of a signal is the measure of the maximum magnitude of the signal from its equilibrium value. It represents the strength or intensity of the signal. A higher amplitude indicates a stronger signal, while a lower amplitude indicates a weaker signal.
What is an order of magnitude?
An order of magnitude is a measure of the size or scale of a value or quantity. It represents a factor of 10 difference in numerical value. For example, if one value is one order of magnitude larger than another, it is 10 times greater.
What applies torque in an automobile engine?
To explain this in simple terms, when the spark plug fires, it burns the gas/air mixture. This causes an explosion. The explosion forces the piston down. This forcing the piston down causes the crankshaft, which the piston is connected to, to turn. The turning of the crankshaft creates a turning force. This force or energy is sent to the transmission by way of the torque converter. This torque converter takes this turning power and turns into energy the tranmission can use. In turn the tranmission does its job and it turns the axis. This is what causes the wheels to turn.
So the torque itself is created by the downward force of the pistons.
What is the torque of a 500 Newton force applied to a 30 meters wrench?
The torque produced by the force is 15,000 Nm (Newton-meters). This is calculated by multiplying the force (500 N) by the distance from the pivot point (30 m). Torque is a measure of rotational force.
Why does a wheel spinning clockwise appear to spin counterclockwise as it speeds up?
Mysteriously, that doesn't happen if you're watching the wheel outside, in sunlight. It only happens if you're inside and the wheel is illuminated by light bulbs, or ... get this ... if you're watching the wheel turn in a movie or on TV.
The intensity of a light bulb actually wiggles, brighter and dimmer, at the rate of the electricity that's running it. In North America, a light bulb has a slight 'flicker' 120 times every second, too fast for your eyes to notice it.
Movies and TV show you a still picture 30 times a second, and your brain fills in the motion. So with most artificial electric lighting, movies, and TV, you're actually seeing a fast series of still pictures.
Now take a wagon wheel with many spokes. In the space between one still picture and the next one, the wheel can turn a little more than one spoke, or exactly one spoke, or a little less than one spoke.
If it turns a little more than one spoke for the next still picture, then a great number of stills will show the wheel turning in the correct direction.
If it turns exactly one spoke for the next still picture, then a great number of stills will show the wheel not turning at all ... the orientation of the spokes is the same in every still.
If it turns a little less than one spoke for the next still picture, then a great numbers of stills will show the wheel turning backward.
If the wheel is standing still and then starts up, it can go through several of these appearances as it climbs to full speed, looking as if it's reversing its direction several times, although the wagon keeps moving forward.
All of this is known as the "stroboscopic" or 'strobe' effect.
Physical quantity coressponding to inertia is rotational motion?
The physical quantity corresponding to inertia in rotational motion is moment of inertia. Moment of inertia is a measure of an object's resistance to changes in its rotational motion. It depends on both the mass and distribution of mass in an object.
-- When you can't turn a stuck nut with 10 pounds of force on a 6-inch wrench, you try the same 10 pounds
of force with a 12-inch wrench. When you're working with things that turn, there's more to the story than
just the magnitude of the force.
-- When you have 20 pounds of lead and you want to build a flywheel, you don't pack it all into the center
and make the wheel as small as possible. You load it at the rim and make it as big as possible. When you're
working with things that turn, there's more to the story than just the amount of mass.
If the wheel is balanced, then gravity produces no net torque on the wheel. The weight of every tiny
bit of the wheel on one side of the pivot ... trying to make the wheel turn one way ... is exactly matched
by the weight of a tiny bit of the wheel on the other side of the pivot, trying to make the wheel turn
the other way.
A balanced wheel freely suspended in the field of earth's gravitation doesn't spontaneously begin to spin.
Angular acceleration is it scalar or vector?
Angular acceleration is a vector quantity because it has both magnitude (rate of change of angular velocity) and direction in rotational motion. The direction of angular acceleration aligns with the axis of rotation it is acting upon.
Is RPM the same as angular speed?
'RPM' is one of many units that can be used to describe angular speed.
Angular speed is (any unit of angle) divided by (any unit of time).
That's exactly what you have in the unit 'RPM'.
'RPM' means "revolutions per minute". "Revolution" is a unit of angle ... it's
exactly 360 degrees ... and "minute" is a unit of time. So RPM is a perfectly
fine unit for measuring/describing angular speed.
What structure is involved in angular acceleration?
Angular acceleration is a measure of how quickly the angular velocity of an object is changing. It involves the object's moment of inertia and the net torque acting on it. When a torque is applied to an object with a certain moment of inertia, it causes the object to accelerate rotationally.
Your set-up is so long that that you ran out of space before you could ask the
question. In fact, you got cut off leaving us with two questions . . . how
heavy should a single weight be, and where should it hang, in order to balance
the whole thing ?
I just noticed that since the stick is 1 meter long, and the three original
weights are placed at the 10cm, 40cm, and 60cm marks, the 10 and the
40 are on one side of the pivot, and the 60 is on the other side, 10 cm
from the pivot. It's all starting to come together.
On one side:
-- There is a weight at the "10cm" mark. That point is 40 cm from the pivot,
and the weight is 100N, so the moment pulling this side down is 4,000 N-cm.
-- There is another weight at the "40cm" mark, and that's 10cm from the pivot.
The weight is 150N, giving us another 1,500 N-cm pulloing this side down.
-- The total moment pulling this side down is (4,000 + 1,500) = 5,500 N-cm.
-- (Plus another 25 x 100 = 5,000 due to the weight of 1/2 the stick. But the
other half is already balancing that much, so I don't think we need to worry
about the weight of the stick at all. This is typical of these meter sticks that
are manufactured by the Red Herring Pedagogical Industries Group LLC of
Eckveldt, South Dakota, and so often used in these Physics demonstrations.)
-- At the "60cm" mark, 10cm from the pivot on the other side, is hanging a
weight of 300N. That gives us 3,000 N-cm of moment working against the two
weights on the first side.
-- In order to balance the whole thing, we have to provide only another
(5,500 - 3,000) = 2,500 N-cm on the second side.
-- All we can say is: The product of (the weight of a single weight hung from
the second side) multiplied by (its distance in centimeters from the pivot) must
be 2,500.
-- The lightest weight that can do the job is 50N, if it's hung at the endof
the stick on the second side, 50cm from the pivot. If we have more weight to
play with, then it can be hung closer to the pivot, just as long as (weight) times (distance from the pivot) = 2,500 N-cm.
Find the torque tau about the pivot due to the weight w of Gilles on the seesaw?
The torque due to Gilles' weight on the seesaw is equal to the weight of Gilles multiplied by the distance from the pivot point to where Gilles is sitting. This torque is given by the equation: torque = weight * distance.
Compare the effects of force and a torque exerted on an object?
Force and torque are both ways to apply a push or pull on an object. However, force is a linear push or pull that causes an object to move in a straight line, while torque is a rotational force that causes an object to rotate around an axis. Forces can cause translational motion, while torques can cause rotational motion.
How does mass affect angular momentum?
Short answer: Angular momentum is proportional to mass. If you double the mass of an object, you double its angular momentum.
Long Answer:
Angular Momentum is a characteristic of rotating bodies that is basically analogue to linear momentum for bodies moving in a straight line.
It has a more complex definition. Relative to an origin, one obtains the position of the object, the vector r and the momentum of the object, the vector p, and then the angular momentum is the vector cross product, L.
L=r X p.
Since linear momentum, p=mv, is proportional to mass, so is angular momentum.
Sometimes we speak of the angular momentum about the center of mass of an object, in which case one must add all of the bits of angular momentum for all the bits of mass at all the positions in the object. That is easiest using calculus.
It should also be said that the moment of inertia, I, is proportional to mass and another way to express angular momentum is the moment of inertia times the angular velocity.
high heat capacity and can absorb more thermal energy before their temperature increases significantly. This property can be useful in applications such as insulation or thermal energy storage.
Examples of how centripetal and centrifugal forces effect your everyday lives?
-- Whenever I am moving and wish to change the direction in which I am moving,
I must find a centripetal force with which to negotiate the curve. Examples include
turning my boat from a northerly heading to a westerly one, banking my airplane
from base leg onto final approach, and walking down the hall and into the bathroom.
-- Centrifugal force has no effect in my everyday lives, since it doesn't exist.
What is the direction of angular acceleration?
Angular acceleration is a vector quantity that points along the axis of rotation according to the right-hand rule. This means if you curl the fingers of your right hand in the direction of rotation, your thumb points in the direction of angular acceleration.
Without detailed information about the shape and mass distribution of his arm, we have to assume that it's
homogeneous and has uniform cross section, so the center mass of his arm is at (71.8 / 2) = 35.9 cm from
the shoulder.
The torque due to the steel ball is (M G R) = (3.61 x 9.78 x 0.718) = 25.35 newton-meters. (rounded)
The torque due to the weight of his arm is (4.7 x 9.8 x 0.359) = 16.54 more newton-meters. (rounded)
The sum of the two torques is 41.89 newton-meters.
What is constant angular speed?
Constant angular speed means that an object is rotating at a steady rate, moving through equal angles in equal time intervals. This means that the object's angular velocity, or rate of rotation, remains the same over time.
What is the Dimensions of rotation speed?
Revolutions per second, or degrees per second - but in advanced mathematics and physics, radians per second is often used. If you have revolutions per second, you can multiply with 2 pi to get radians per second.
Is angular displacement is a vector?
angular displacement is a vector quantity when theta (angle) is small, otherwise it is scalar.
1). If there is no force on the object, then it keeps moving in a straight line.
If you want it's path to bend away from a straight line, then you need a force
in order to accomplish that.
2). The force acts in the direction that bends the path away from a straight line. In
other words, in the direction in which the path curves. For a closed orbit, the force
has to be toward the center, or at least close to it. Conveniently, that's where the
big massive body happens to be, which sets up a nice, two-way gravitational force
between the central body and the orbiting body. Gravity is the centripetal force, and
it always points both ways between the two bodies, trying to draw them together.
How do you figure out centripetal force problems?
-- Take all the information given in the problem.
-- Gather in everything you know about centripetal force, especially including
any equations, formulas, or laws that mention any of the given information or
the information that you're supposed to find.
-- Use the given information, plus the things you know from having studied
the subject, to find the missing information.
