Force and Motion: Finding final velocity given force, mass, time, and initial velocity

Описание: Sometimes, you have to combine formulas and concepts in order to find what you are looking for. In this video, final velocity is found given force, mass, time, and initial velocity.


The problem in this video:

A force of 20 N acts on a object with a mass of 5 kg. If it has an initial velocity of 10 m/s, what is its final velocity after an elapsed time of 6 seconds?



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NOTICE:

Video shot at Lowell High School, Tricreek School Corporation, Lowell, Indiana.

The producer of this video offers it as-is to viewers who are free to use it at their own risk. Errors and omissions are not the responsibility of the producer, nor of anyone associated with its production.

Lowell High School, Tricreek School Corporation, Lowell, Indiana and The State of Indiana are not responsible for the production or content of this video.

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No dropped sharpies were seriously harmed in the filming or production of this video.

NOTES:

Find vf where

a is not given and

m = 5 kg
F = 20 N
vi = 10 m/s
t = 6 s


First,
find a using Newton's 2nd Law where

F = 20 N
m = 5 kg

F = ma
20 N = (5kg)(a)
20 N / 5 kg = a
4 m/s/s = a


After finding that

4 m/s/s = a

use a to find vf where


vi = 10 m/s
t = 6 s

vf = vi + at
vf = 10 m/s + (4 m/s/s)(6 s)
vf = 10 m/s + 24 m/s
vf = 34 m/s