The graph shows position versus time for an object moving with constant acceleration. What is the final velocity of the object at t = 10 s? Assume the initial velocity at the origin is 1 m/s.
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Remark
The object is moving at a constant acceleration. The acceleration is not given, but it does permit you to use d = (vi + vt)*t/2
Givens
vi = 1 (This is important.
d = 21 m (read from the graph) You have to go up just a little bit from 20
vf = ???
t = 10 s
Solve
d = (vf + vi)*t/2
21 = (vf + 1) * 10/2 Multiply by 2
42 = (vf + 1) * 10 Divide by 10
4.2 = vf + 1 Subtract 1
4.2 - 1 = vf
vf = 3.2 Answer
The graph seems to show the position at t=10 s to be x=21 m. Thus, the position has changed at the average rate of
... (21-1) m/(10 s) = 2.0 m/s
The average is half the sum of initial and final velocities, so we have
... 2.0 m/s = (1/2)(1.0 m/s + vf)
... 4.0 m/s - 1.0 m/s = vf = 3.0 m/s
The final velocity is 3.0 m/s.