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When to use law of momentum to find velocity rather than law of conservation of energy?
While energy is ALWAYS conserved, this isn't always useful for calculations, since MECHANICAL ENERGY - the energy that can be easily calculated - is NOT always conserved. On the other hand, momentum is always conserved, whether a collision is elastic or inelastic. (In an elastic collision, energy is also conserved.) Thus, conservation of momentum is often more useful for calculations involving collisions.
What else can I help you with?
Why two objects move in opposite direction one will have positive momentum and other negative momentum?
Quite simply, this means that momentum is a vector quantity; the direction is relevant. This is useful, for example, for calculations involving the conservation of momentum. Actually momentum is the product of velocity and mass, and velocity is also a vector quantity - thus, in this example, one object will have a positive velocity (more precisely: a positive component of the velocity along the x-axis, for example), the other, negative. Multiplying this velocity by the mass will also give a quantity which may be positive or negative (or rather, have positive or negative components).
Which is not part of the equation for angular momentum?
Rotational speed. Rotational speed is typically used to calculate rotational kinetic energy rather than angular momentum, which is determined by rotational inertia and angular velocity.
Why does bouncing of an object result in a greater change of momentum rather than just colliding?
Momentum is the mass multiplied the change in velocity. If you think about it, bouncing an object means that it comes back from whatever it bounced against, giving it a negative velocity. This means that the change in velocity for bouncing is greater than for colliding because in an inelastic collision like the one described, the velocity goes to zero.
A spaceship has a momentum of 20 000 kg-ms to the left and a mass of 500 kg What is the magnitude of its velocity?
momentum = mass x velocity, so velocity is momentum/mass. If the question asks for the magnitude then it's probably the absolute magnitude rather than a directional value (which would be negative as the space ship is heading to the left.
Which would have greater effect on kinetic energy of an object - doubling the mass or doubling the velocity?
Doubling mass affects kinetic energy in that the greater the mass, the greater the kinetic energy. OK, but if you have a 10kg mass traveling at 2m/s and it bumps into and sticks to a 10g mass, the resultant speed would be 1m/s. The momentum stays the same. KE before is 10*2*2/2= 20, while the KE after is 20*1*1/2= 10. So it is not that the above answer is wrong, but rather, you question is not clear.
How is momentum used to determine collisions?
Momentum is traditionally used with Newtonian thinking in the conservation of energy, witness the desk toy with the 5 steel balls suspended by threads that cycle back and forth. Momentum here is based on simply equilibroum of the product of mass and velocity. On the Einstein relativity thinking, applicable to motions of objects approaching the speed of light, the laws of Newtonian logic fall apart, and one has to consider energy, mass and time. Here, momentum does not translate into velocity but rather distortions in time and mass.
Why two objects move in opposite direction one will have positive momentum and other negative momentum?
Quite simply, this means that momentum is a vector quantity; the direction is relevant. This is useful, for example, for calculations involving the conservation of momentum. Actually momentum is the product of velocity and mass, and velocity is also a vector quantity - thus, in this example, one object will have a positive velocity (more precisely: a positive component of the velocity along the x-axis, for example), the other, negative. Multiplying this velocity by the mass will also give a quantity which may be positive or negative (or rather, have positive or negative components).
Which is not part of the equation for angular momentum?
Rotational speed. Rotational speed is typically used to calculate rotational kinetic energy rather than angular momentum, which is determined by rotational inertia and angular velocity.
What is consseveration?
Conservation has two definitions that I know of in this category. One is in scientific laws like conservation of angular momentum or conservation of energy. Conservation in this sense means that that element can't be created or destroyed. Conservation of energy, for example means that energy isn't created or destroyed, but rather it changes form (like from chemical energy to heat). The other conservation is like wildlife conservation which includes programs where people try to conserve the Earth's resources, wildlife, etc.
Why does bouncing of an object result in a greater change of momentum rather than just colliding?
Momentum is the mass multiplied the change in velocity. If you think about it, bouncing an object means that it comes back from whatever it bounced against, giving it a negative velocity. This means that the change in velocity for bouncing is greater than for colliding because in an inelastic collision like the one described, the velocity goes to zero.
A spaceship has a momentum of 20 000 kg-ms to the left and a mass of 500 kg What is the magnitude of its velocity?
momentum = mass x velocity, so velocity is momentum/mass. If the question asks for the magnitude then it's probably the absolute magnitude rather than a directional value (which would be negative as the space ship is heading to the left.
Which would have greater effect on kinetic energy of an object - doubling the mass or doubling the velocity?
Doubling mass affects kinetic energy in that the greater the mass, the greater the kinetic energy. OK, but if you have a 10kg mass traveling at 2m/s and it bumps into and sticks to a 10g mass, the resultant speed would be 1m/s. The momentum stays the same. KE before is 10*2*2/2= 20, while the KE after is 20*1*1/2= 10. So it is not that the above answer is wrong, but rather, you question is not clear.
How do photons have momentum if they dont have mass?
Photons have zero rest mass, but at the speed at which they move ... always the speed of light ... they have momentum, energy, and mass. Photon energy = (h n) Kinetic energy = (1/2 m c2) = (h n) ===> mass = (2 h n / c2) Momentum =(m c) = (2 h n / c) (h = Planck's constant, n = frequency, c = speed of light)
Find the velocity and momentum of electron whose kienetic energy equals its rest mass which is 9.1110 power -31?
I rather believe the question ask the kinetic energy equals to rest mass energy of electron. If it would state the figure of rest mass of 9.111 x 10-31 kg = kinetic energy of 9.111 x 10-31 J the unit should be given more clearly. It is given rest mass of 9.111 x 10-31 kg and rest mass energy is calculated by E = mC2 The kinetic energy is Ek = mC2/(1-v2/C2)0.5 - mC2 and for Ek = mC2 It is solving for mC2 = mC2/(1-v2/C2)0.5 - mC2 --> 2mC2 = mC2/(1-v2/C2)0.5 2 = 1/(1-v2/C2)0.5 Solve for v should not be too hard for you. Now, the momentum You must notice that when v is close to speed of light (C), you can't simply use momentum = mv but rather P = mv/(1-v2/c2)0.5 Use v obtained from above to solve for momentum.
What factors affect the momentum of an object?
Its mass and its velocity. In Newtonian mechanics you have a rather simple formula for calculating the momentum of an object: p = m * v Where p is the momentum, m the mass, and v the velocity. In special relativity (i.e. when the speed approaches that of light) you have to use a different formula: p = gamma * m * v Where gamma is the gamma factor given by 1/sqrt(1-sqr(v/c)), with c the speed of light. This formula becomes the Newtonian one in the limit of v going to zero.
What is mommentum in science?
Momentum is a concept in physics that combines both the mass and velocity of an object. Basically it is the velocity of an object multiplied by its mass. Even though it relates very simply to the mass and velocity of an object it is still commonly used because it simplifies a great number of equations. Also some descriptions of reality are more convenient when using the mass and momentum rather than mass and velocity. This is especially true in particle physics where the simple relation illustrated above does not quite hold (a new factor is required, called the gamma factor) because the speeds approach those of light, and a momentum based model is more easy to work with.
How do you calculate speed and momentum?
Speed is defined as distance travelled per unit of time (for example, miles per hour, or kilometers per hour, feet per second, etc.). Momentum is mass times velocity. Velocity is not exactly the same thing as speed; it is the speed plus the direction. That way, two objects that are moving in the opposite direction have opposite momentum, and when the collide, the momentum can cancel (if they don't bounce apart) rather than adding up to twice the momentum. Actual calculations of these sorts of problems involves calculus, because speed and momentum can change continuously, so you need a mathematical system that is designed to deal with that kind of change.
