# To find time

Serj
I want to know how to find the time it takes for a mass to reach a velocity if a force is applied to it.

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Mentor
One way is to apply Newton's 2nd law to find the acceleration, then integrate--or apply kinematic equations--to find the time: $v_f = v_i + a t$.

Another (equivalent) way is to use the "impulse-momentum" theorem: $F \Delta t = m \Delta v$.

Serj
i'm terrible at math, can you isolate time on one side of the equation?

Homework Helper
What equation are you using?

Serj
Vf=Vi + at

Staff Emeritus
Serj said:
I want to know how to find the time it takes for a mass to reach a velocity if a force is applied to it.

Note that there is no mention of a constant force being applied here.

Zz.

cscott
Serj said:
Vf=Vi + at

$$t = \frac{v_f - v_i}{a}$$

Make note of what ZapperZ said, though.

Staff Emeritus