an object of mass 'm' is moving with a momentum 'p'. which one represents its kinetic energy?

Answer 1

Well you need both. Momentum is composed of mass and velocity, p=mv (simplified, I know). Kinetic energy is usually written as E= 1/2mv^2. It can be rewritten to use momentum: E=p^2/(2m). In either case you need information about the velocity/momentum and the mass. Note that momentum is a conserved quantity, along with energy.

Answer 2

Momentum = mass * velocity
KE = 1/2 * m * v^2

Beginning students often confuse kinetic energy and momentum. Kinetic energy and momentum are NOT THE SAME!

An important difference is that momentum is a vector quantity - it has a direction in space, and momenta combine like forces do. Kinetic energy is a scalar quantity - it has no direction in space, and kinetic energies combine like "regular numbers".

Suppose that you were captured by an evil physicist who gave you the following choice:

You must either:

Stand in front of a 1000 kg. truck moving at 1 m/s, or
Stand in front of a 1 kg. meatball moving at 1000 m/s.
What's your choice?

Hopefully, you picked the truck! It's a big truck, but it is moving rather slowly (about walking speed), so assuming you don't fall down when it hits you (That would be bad...) the truck is just going to bump into you and move you out of the way.

On the other hand, you probably suspect intuitively that the meatball is a very dangerous object. It isn't that massive, but it is moving very fast (about 10 football fields per second) - and when it hits you it would do considerable damage to you, and keep going!

Consider the momentum and kinetic energy of the truck and the meatball:

Truck:

Truck's momentum = mv = (1000 kg)(1 m/s) = 1000 kg m/s
Truck's kinetic energy = 0.5 mv2 = (0.5)(1000 kg)(1 m/s)2 = 500 Joules

Meatball:

Meatball's momentum = mv = (1 kg)(1000 m/s) = 1000 kg m/s
Meatball's kinetic energy = 0.5 mv2 = (0.5)(1 kg)(1000 m/s)2 = 500 000 Joules

We know intuitively that the meatball is more dangerous than the truck, yet the momenta of the truck and the meatball are the same. On the other hand, the meatball has 1 000 times the kinetic energy of the truck! Clearly, momentum and kinetic energy tell different things about an object!

Answer 3

Momentum has been coined to facilitate calculation.However with time based on relativity theories it has become to mean an object which has displaced from it original rest position.

When an object is displaced it is said to have changed its state of energy;It is now moving,Hence when something is moving it is said to have motional Energy. Hower the mass has a structural energy content, ,and this energy content is said to be its Energy at rest.
Hence all masses have a structure and contain structural energy
The energy of structure is the product of the mass and the velocity of light squared. When A mass starts to move it experiences a change in structural energy and at the same time acquires energy of motion. So to distinguish from rest energy (potential) the word momentum is used to mean that the mass is moving.
The definition of linear moment is mass x velocity.
and angular momentum refers of a revolving mass in a gravity field.;defined as linear momentum x its radius of gyration.

In the motion of radiated masses angular momentum is used because the energy coming out of the atom is rotational energy being tranformed into a diferent frame of reference which is now linear motion known as kinetic energy.
So if the mass change is neglible and you kow the velocity moving mass its average kinetic energy can be calculated.
The formula for radiation energy is ; E= angular momentum x the radiation frequency.

Angular momentum constant is = h which is plancks constant.
P = mass x velocity
E = P x r x f,which is = to h x f
where r is radius of gyration and f is frequency of radiation

Answer 4

Kinetic Energy=1/2*mass*velocity^2
=1/2*m*(p/m)^2
(because velocity=momemtum/mass)
=1/2*m*p^2/m^2
=1/2*p^2/m

Answer 5

Kinetic energy is the energy of mass in movement. If the mass is at rest it has a velocity (v) of 0m/s, so it is poltential energy.
The formulae is simple.

ke=1/2mv

if a mass of 1 kg has a velocity lets say of 5m/s

Then ke=1/2mv
ke=1kgX5m/s/2> ke=2.5 joules (or 2.5kg per meter/segond)

Answer 6

E = P^2 / (2*m)

Answer 7

p=m*v
where,
where p is the momentum, m is the mass, and v the velocity.

The kinetic energy of an object is related to its momentum by the equation:
Ek=p^2/2*m
Ek=(m*v)^2/2*m
Ek=m^2*v^2/2*m
EK=m*v^2/2
Ek=1/2 * m * v^2

Answer 8

Well lets see. I believe it would be momentum. The amount of energy possible is proportional to the amount of momentum carried * the mass.

Answer 9

destroy it into aspects. the unique momentum at P became (mv sqrt(2)/2, mv sqrt(2)/2). The horizontal factor is mv * cos(theta) = mv sqrt(2)/2, and the vertical factor is mv * sin(theta) = mv sqrt(2)/2. the main suitable momentum at Q is (mv sqrt(2)/2, - mv sqrt(2)/2). The horizontal factor is an identical, the vertical factor is the different of the unique. the version between those is (0, mv sqrt(2)) which has a value of mv sqrt(2).

Answer 10

P = m*v (1)
and
K = (1/2)*m*v^2 (2)

Solving (1) for v we get
v=P/m (3)
Combining (2) and (3) we get
K = (1/2)*m*(P/m)^2 ->
K = (1/2)*P^2/m ->
K = P^2/(2*m)