AP Physics 1


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E. Solving Problems using the motion equations





Ex 3) Starting from rest, an object accelerates at a rate of 12 m/s2. What is the velocity of the object at the end of 3 seconds?


Vi = 0 (Starting from rest)

a = 12 m/s2

Vf = ?

t = 3.0 seconds


a = (Vf - Vi)/t


12 m/s2 = (Vf - 0)/3.0 secs

(Cross Multiply and Solve)


Vf = 36 m/s




Ex 4) An object at 100. m/s accelerates at a rate of 120. m/s2. What will the velocity of this object be after .100 seconds?


a = (Vf - Vi)/t


120. m/s= (Vf - 100. m/s)/.100 s


• Cross Multiply


12.0 = (Vf - 100.)



Vf = 112 m/s



3 ways to have non-zero acceleration



(to change velocity):


Speed Up

• Slow Down


• Change Direction



F. Motion Terms and Direction

A whole branch of mathematics is required to deal with numbers that have direction



This is why it is important to know which motion information has direction


Vector - a quantity that includes magnitude (a number) & direction


ex) displacement, acceleration, velocity



Scalar - a quantity that includes magnitude (a number) only



ex. time, distance, speed





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