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Kinematics
Kinematics is the study of how a body moves. This includes linear motion, angular motion, and rotational motion.
3,459 Questions
How are speed and velocity different?
Speed is the distance travelled in a given period of time and is measured in metres per second or miles per hour (ie 'distance' per 'unit of time'). It is always a positive number. Velocity, however,, is the sppeed of an object in a given direction. So that if you define ''forwards' as a positive velocity, then if the object travels 'backwards', that would be classed as a negative velocity. So, if a car travels forwards, say, at 30 mph, its speed will be 30mph and its velocity will also be 30mph. However, if the car returns at the same speed, its speed will still be 30mph but its velocity will be - 30mph (minus 30mph) as the car is travelling in the opposite direction. This may seem a pointless exercise, but in equations of motion that involve speed, velocity, accceleration, time and so on, the direction of travel is important and so the velocity is used rather than speed. The concept of velocity is used in space travel, satellite technology, calculating flight paths, calculating missile trajectories and so on and so direection of travel - and hence velocity - is of vital importance.
Kinetic energy is the energy possessed by an object due to its motion. It depends on both the mass and velocity of the object, and is defined by the equation KE = 0.5 * m * v^2, where KE is kinetic energy, m is the mass of the object, and v is the velocity.
== == Momentum is the product of the mass of an object multiplied by its velocity (or speed). Momentum is conserved so if a moving object hits a staionary object the total momentum of the two objects after the collision is the same as the momentum of the original moving object.
Does an object with momentum always have energy?
Not if it's potential energy. Only objects with kinetic energy have momentum.
What is the difference between kinetic energy and potential energy?
Kinetic energy is the energy in the movement.
Potential energy is stored energy, ready to be used.
K.E-motion energy
P.E-energy stored during displacement of springs that tend to restore to original position of spring
Kinetic energy is the energy found in every object in motion .
Gravitational Potential Energy is the enegry stored in an object because of its height. For example, the energy that water has before it goes over a waterfall. Chemical potential energy is the energy that a substance can release by undergoing a chemical reaction, for example gasoline which releases energy when it is burned. Mechanical potential energy would be the kind stored in a compressed spring. Radioactive materials such as uranium have nuclear potential energy.
Kinetic energy is the energy of motion.. while something is moving.. and potential energy is the energy being stored up for the object TO move.
A ball rolling has kinetic energy... when you pull back a spoon to throw food at someone, when you pull back and hold it there, it has potential energy (potential to be kinetic, that is)
Potential energy is the capacity for doing work that a body possesses because of itsposition or condition. While kinetic energy is energy a body possesses because it is in motion.
kinetic energy is moving energy or energy used in preforming an action.
potiental energy is sitting energy or energy that is being saved up.
potential- when energy is stored.
kinetic- when energy is moving
Potential energy is stored energy, when building up to it's highest point the energy is released as kinetic energy. For example potential energy is the energy gathered when moving slowly up an amusement park ride, when you reach the top the potential energy reaches it's limit and is realeased as kinetic energy when you rocket downwards.
Does the path of an object's projectile motion depend on the angle?
Yes, the angle at which an object is projected affects the path of its projectile motion. A higher launch angle will result in a longer flight time and distance, while a lower launch angle will result in a shorter, more vertical trajectory.
Speed doesn't matter at all, The car that crossed the finish line first got on it's way earlier and crossed the timers first. This is a drag race not a speed trial. You may have been 50 miles an hour faster at the finish line but you got a bad start.
What are the assumptions used to develop the kinematics model of circular motion?
The main assumptions in developing the kinematics model of circular motion are that the object is moving along a circular path at a constant speed, which implies uniform circular motion. Additionally, it is assumed that there is no tangential acceleration, meaning that the speed of the object remains constant. Finally, the assumption is made that the object's motion can be described using angular quantities such as angular displacement, velocity, and acceleration.
The total distance the postal worker has traveled is the sum of the distances walked in each direction. So, the total distance traveled is 161m + 164m = 325m.
Objects that do not accelerate?
All objects accelerate if the forces acting on them are not balanced.
Derive the kinetic energy operator for a system of 4 atoms using Jacobi coordinates?
= Quantum theory of four-atom reactions using arrangement channel hyperspherical coordinates: Formulation and application to OH+H2H2O+H =
An arrangement channel hyperspherical coordinate method for performing quantum scattering calculations on four-atom reactions is formulated. This method treats the vibrational and rotational states in different arrangement channels by a close-coupling expansion in nonorthogonal functions. The method is applied to the calculation of state-to-state probabilities for the OH+H2H2O+H reaction. Good agreement is found with cumulative and state-selected reaction probabilities previously calculated by other methods. The major advantage of this general approach is that the whole S matrix can be obtained in a single calculation.
Give and example for the conservation of energy?
An example of law of conservation of mass is when wood is burned the gases released are part of the original mass of the wood.The air would then contain part of the mass and the ashes would contain.(this is an example of the law of conservation of mass and energy)
Acceleration is caused by any forces?
Roughly speaking, acceleration is caused by destroying the balance of forces on an object.
What is the top speed of the baguti vayron?
The top speed of the Bugatti Veyron is around 253 mph (407 km/h).
What is the term used to describe the rate of an object's movement?
The term used to describe the rate of an object's movement is speed or velocity. Velocity is the same as speed but also measures direction.
What is an example of kinetic energy decreasing and potential energy increasing?
In a rollercoaster, potential [[i believe]] is the highest when it starts, or rises, and vice versa for descreasing kinetic energy. Throwing a basketball in the air, when it reaches it's highest point, it's potential energy is at it's maximum and the kinetic energy is low for a moment until it comes back down
If two objects meets head-on with the same mass and speed what is the collision?
Provided the objects are of identical density and structure, particles would exit on an axis perpendicular to the axis of attraction, until secondary fragment collisions alter their trajectory.
If the density of the objects is significantly different, the object of lesser density would be destroyed with the object of greater density taking only superficial damage if any. Physical shape and the cleavage of the material could also play a part in this.
(o well hope this is right lol dont pay me no mind tho)
When you increase the height of a ramp, the efficiency for kinetic energy decreases because you are doing work against gravity to lift the object higher. This means less of the initial potential energy is converted into kinetic energy compared to when the ramp is lower.
Who the Chinese acrobats in incredible balancing act are in equilibrium?
The Chinese acrobats in the incredible balancing act are skilled performers who have undergone rigorous training to develop their strength, balance, and flexibility. Their precise movements and control allow them to achieve incredible feats of balance and equilibrium that captivate audiences around the world.
What is the relationship between momentum and mass?
The more the mass, the more momentum you will need for an object to speed up more, or accelerate.
Is velocity a scalar quantity or vector quantity?
Velocity is a vector.
Its magnitude is called 'speed'.
In an elastic collision between two objects do both objects have the same kinetic energy after the collision as before?
Let's do the problem and see
The problem below will prove that in an elastic collision between two objects the objects do not have the same kinetic energy after the collision as before?
But the KE before collision = KE after collision
A 2 kg object with velocity of 8 m/s E hits a 5 kg object with a velocity of 5m/s W. What is the velocity of both objects after colision?
East is positive, West is negative
Draw a picture showing the 2 objects before and after collisions.
…..8 m/s……………....-5 m/s………….V2…………….V5
...2kg object..-->….<--5 kg object…..2kg object…….5kg object W……………………………………………………………….E
Mom = +16………..Mom = -25………..2V2……………5V5
Momentum = mass * velocity
Since the 5 kg object has more momentum, both objects will continue to move West. They should have negative velocities!!
Momentum = mass * velocity
Total momentum before collision = (2 * 8) + (5 * -5) =
Total momentum before collision = 16 + -25 = -9
Total momentum before collision = -9
Total momentum after collision = (2 * V2) + (5 * V5)
Momentum is always conserved.
Total momentum after collision = Total momentum before collision
2V2 + 5V5 = -9 = (add - 2V2 and +9 to both sides)
2V2 = -9 - 5V5 , (divide by -2)
V2 = -4.5 - 2.5V5
Eq. momentum = V2 = -4.5 - 2.5V5
Since the collision is elastic, kinetic energy is conserved
KE before collision = KE after collision
KE ½ mass * velocity ^2
KE before collision = ½ * 2* 8^2 + ½ * 5 * 5^2 =
KE before collision = 64 + 62.5 =
KE before collision = 126.5
KE after collision = ½ * 2 * V2^2 + ½ *5 *V5^2
KE before collision = KE after collision
126.5 = ½ * 2 * V2^2 + ½ *5 *V5^2
126.5 = V2^2 + 2.5 *V5^2
Eq. energy = V2^2 + 2.5 *V5^2 -126.5 =0
Now we have 2 equations in 2 unknowns
Substitute the value of V2 from Eq.m into Eq.e
V2 = -4.5 - 2.5V5
(-4.5 - 2.5V5)^2 + 2.5V5^2 -126.5 = 0
(20.25 + 22.5V5 + 6.25V5^2) + 2.5V5^2 -126.5 =0
Add (6.25V5^2 + 2.5V5^2) = 8.75V5^2
Subtract (20.25 - 126.5) = -106.25
8.75V5^2 + 22.5V5 -106.5 =0
Use quadratic equation to solve for V5
V5 =[ -22.5 ± [22.5^2-(4 * 8.75 * -106.25)]^0.5] ÷ (2 * 8.75)
V5 = [-22.5 ± [506.25 + 3718.75]^0.5] ÷ 17.5
V5 = [-22.5 ± [4225]^0.5] ÷ 17.5
The square root of 4225 = ± 65, I will try +65 first and try add +65 first.
V5 = [-22.5 + 65] ÷ 17.5
V5 = +42.5 ÷ 17.5
V5 = +2.42857
This means the 5 kg object is going East. I made this statement at the beginning. "Since the 5 kg object has more momentum, both objects will continue to move West." V5 = +2.4286 is wrong
I will try subtract +65.
V5 = [-22.5 - 65] ÷ 17.5
V5 = -87.5 ÷ 17.5
V5 = -5
That can not be true, because that was the velocity of the 5 kg in the beginning.
I will try using - 65 for the square root of 4225, and add.
V5 = [-22.5 + -65] ÷ 17.5
V5 = -87.5 ÷ 17.5
V5 = -5
That can not be true, because that was the velocity of the 5 kg in the beginning.
Last but not least, I will using - 65 for the square root of 4225, and subtract.
V5 = [-22.5 - -65] ÷ 17.5
V5 = +42.5 ÷ 17.5
V5 = +2.42857
I know the answer has to be V5 = -2.42857.
If the -22 was +22.5, I would get the correct answer..
If you find the mistake, email me at morrison60957@yahoo.com
V5 = [+22.5 - 65] ÷ 17.5
V5 = -42.5 ÷ 17.5
V5 = -2.42857
I will copy, paste the area where I believe my mistake is at the bottom of this work. If you find my mistake let me know!!
V5 = -2.42857
Eq. momentum = V2 = -4.5 - 2.5V5
V2 = -4.5 - (2.5* -2.42857)
V2 = -10.5714
Let's see if the momentum = -9
Total momentum after collision = (2 * -10.5714) + (5 * -2.42857)
Total momentum after collision = -21.142853 + 12.14285 = -9.000003
Now let's see if the Kinetic energy is conserved
KE before collision = 126.5
KE after collision = ½ * 2 * V2^2 + ½ *5 *V5^2
126.5 = ½ * 2 * (-10.5714)^2 + ½ *5 *(-2.42857)^2
126.5 = 111.754498 + 14.75588061
126.5 ≈ 126.49993786 OK
KE before collision = 64 + 62.5
KE of 2 kg object = 64 J
KE of 5 kg object = 62.5 J
Sum of KE = 126.5
KE after collision = 64 + 62.5
KE of 2 kg object after collision = 111.754498 J
KE of 5 kg object after collision = 14.75588061 J
Sum of KE after collision = 126.49993786
I have proved that in an elastic collision between two objects the objects do not have the same kinetic energy after the collision as before?
But the KE before collision = KE after collision
Below is the work where I suspect I have made a mistake, If you find the mistake, email me at morrison60957@yahoo.com
Momentum = mass * velocity
Total momentum before collision = (2 * 8) + (5 * -5) =
Total momentum before collision = 16 + -25 = -9
Total momentum before collision = -9
Total momentum after collision = (2 * V2) + (5 * V5)
Momentum is always conserved.
Total momentum after collision = Total momentum before collision
2V2 + 5V5 = -9 = (add - 2V2 and +9 to both sides)
2V2 = -9 - 5V5 , (divide by -2)
V2 = -4.5 - 2.5V5
Eq. momentum = V2 = -4.5 - 2.5V5
V2 = -4.5 - 2.5V5
(-4.5 - 2.5V5)^2 + 2.5V5^2 -126.5 = 0
(20.25 + 22.5V5 + 6.25V5^2) + 2.5V5^2 -126.5 =0
Add (6.25V5^2 + 2.5V5^2) = 8.75V5^2
Subtract (20.25 - 126.5) = -106.25
8.75V5^2 + 22.5V5 -106.5 =0
The condition you are referring to is called temperature. Temperature is a measure of the average kinetic energy of the particles in a substance, such as air. When the average velocity of atmospheric molecules is not zero, it indicates that the substance has a non-zero temperature.
