Thread: velocity of car

(a) what was the initial velocity of the car?explain
(b)was the car going faster at B or at c.?why?
(c)For each point A,B and c,state whether the car was speeding up or slowing down.explain your answer for each point
(d)what happened between D and E.explain

What else did the question say? Also, is the x-axis time, speed, or distance? What about the y-axis?

attaching the diagram again
y - axis ::: S(t)
x axis :: t

Originally Posted by bobby77

(a) what was the initial velocity of the car?explain
(b)was the car going faster at B or at c.?why?
(c)For each point A,B and c,state whether the car was speeding up or slowing down.explain your answer for each point
(d)what happened between D and E.explain

For all of these remember that velocity at a point is the slope tangent to the curve at that point.

a) The slope of the tangent is zero, thus the car started from rest.

b) It looks to me as if the slope at both points is zero, thus the car is stationary at both B and C. Thus they have the same speed, 0.

c) As I said in b), at B and C it looks like the car is at rest. At A the curvature is positive, so the car is speeding up. (The curvature is the second time derivative. We can see that the curvature is positive by noting that that section of the graph looks like a piece of an opening upward parabola.)

d) It looks to me like the slope of the line stays at zero between D and E, so I would say the car was at rest during this time period.

-Dan