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course Phy 201
An object is given an unknown initial velocity up a long ramp on which its acceleration is known to have magnitude 12 cm/s^2. .206 seconds later it passes a point 7.4 cm up the ramp from its initial position. •What are its possible initial velocities, and what is a possible scenario for each?
• What is the maximum distance the object travels up the ramp?
vAve = ‘ds/ ‘dt
vAve = 7.4cm / .206sec
vAve = 35.9cm/sec
vAve = (v0+vf) / 2
If the magnitude of acceleration is 12cm/sec^2 then it could be either positive or negative
which means vf or v0 can = 0cm/sec
assuming v0=0
vf= 2*(35.9cm/sec)
vf= 71.8cm/sec
So initial velocities can range from 0cm/sec to 71.8cm/sec. It is either accelerating or decelerating.
max dist is equal in both directions
If v0 = 0, vf = 71.8 cm/s and `dt = .206 sec, the magnitude of the acceleration is much greater than 12 cm/s^2. So your assumption leads to a contradiction.
You can't assume anything about v0 or vf.
You are given two possible values for a, and you are given `dt and `ds. These three quantities completely determine the others, including v0 and vf.
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