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E. Solving Problems
using the motion equations
Motion Map
1st sec / 2nd sec / 3rd sec 12 m/s / 24 m/s / 36 m/s
Ex 3) Starting from rest, an object accelerates at a rate of 12 m/s^{2}. What is the velocity of the object at the end of 3 seconds?
V_{i} = 0 (Starting from rest) a = 12 m/s^{2} V_{f} = ? t = 3.0 seconds
a = (V_{f}  V_{i})/t
12 m/s^{2} = (V_{f}  0)/3.0 secs (Cross Multiply and Solve)
Ex 4) An object at 100. m/s accelerates at a rate of 120. m/s^{2}. What will the velocity of this object be after .10 seconds?
Ex 4) An object at 100. m/s accelerates at a rate of 120. m/s^{2}. What will the velocity of this object be after .100 seconds?
a = (V_{f}  V_{i})/t
120. m/s^{2 }= (V_{f}  100. m/s)/.100 s
• Cross Multiply
12.0 = (V_{f}  100.)
V_{f} = 112 m/s
3 ways to have nonzero acceleration
(to change velocity):
• Speed Up
• Slow Down
• Change Direction
F. Motion Terms and 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
Invisible Flame
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