# Physics QuestionsÉ?

How do you calculate momentum?

How would you rearrange the equations J=m(vf-fi) when you are trying to isolate vf? And the equation F=ma when you are trying to isolate a?

### 1 Answer

- dawonzcherLv 56 years agoFavorite Answer
Q#1) How do you calculate momentum?

Answer : Although momentum alone cannot be calculated by itself unless there is an outside force that can make the object move first, then trough its movement can momentum be calculated through the inter-action of the outside force.

Impulse = momentum

where: Impulse= Force x change in time

Momentum = Mass x change in velocity

The final equation would be:

F (t) = m (v)

Q#2) How would you rearrange the equations J=m(vf-fi) when you are trying to isolate vf?

J=m(vf -f i) ..( first, multiply m to all the member inside the parenthesis)

J = mvf - mfi...( then transpose the term "mfi" to the other side, but the sign changes from minus to plus)

J + mfi = mvf ..(then multiply both sides by 1/m, to cancel m on the right)

(J + mfi ) / m = vf .( then, that's it)

Or J/m + fi = vf

Q#3) F=ma, when you are trying to isolate a?

We try to isolate "a" when we are told to find the acceleration.That is when both the "force" and the "mass" is given. Same thing happen that we try to isolate "m" when we are told to find the mass of an object, with both "F" and "a" are given.

So: a = F / m ( the units is m/s^2) ; Do always remember that "A force of 1 N = kg-m/s^2)"

a = F in(kg-m/s^2) / m in Kg = m/s^2 ...(kg cancels out)

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