# What is momentum? and how to derive the formula..

2
by Deleted account
it is quantity of motion of a moving body ,the product of its mass and velocity. lets mass = m and velocity of that moving body = v then momentum =mv
no it is force directly proportional to velocity and inversely to mass, what is that??
no it is directly proportional to both velocity and mass and its unit is kg m/s
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2014-08-15T19:59:29+05:30
It is the product of mass and velocity. Its SI Unit is kg m/s. It is vector quantity due to the velocity. It denoted by 'p'.
p = m × v
what it means, a product of mass and velocity???
same thing i want to say ................. its absolutely right ans
its denoted by p....
got it ?
2014-08-15T20:23:50+05:30
Initial linear momentum = mu
final linear momentum = mv
change in linear momentum in 't' seconds = mv - mu
rate of change of linear momentum = mv - mu/ t
according to Newton's second law of motion, F is directly proportional to mv-mu/t OR
F is directly proportional to m(v-u)/t
from equations of motion, v-u/t = a
Therefore, F is directly proportional ma⇒F=kma where 'k' is constant of proportionality
Thus, F = kma⇒(unit force) = k(unit mass)(unit acceleration)
1=k × 1×1
Thus, F = ma

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means
the value of quantity F is defined such that k is = 1.
i am not able to understand why we will take k as 1 only...
'k' is a constant value in which we can can put value but there is no need for think about in class 9 it is the matter of above class.