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simple clarification

red and white kop!

Junior Member
Joined
Jun 15, 2009
Messages
231
ok this is a kinematics thing.
s(displacement)=93, v(end velocity)=42, t(time)=3/2, find a (acceleration)
so i used s= vt -0.5at^2 and got a= -80/3
however the answer is (+ or -) 80/3, and i dont know why. can someone clarify?
 

mmm4444bot

Super Moderator
Staff member
Joined
Oct 6, 2005
Messages
10,158
80/3 is acceleration (the velocities are increasing).

-80/3 is deceleration (the velocities are decreasing).

Both are given because we don't know whether or not the object is accelerating or decelerating at the given point in time; without more information, both scenarios are possible, yes?
 
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