Question

Two identical objects, A and B, move along straight, parallel, horizontal tracks. The graph above represents the position as a function of time for the two objects.
(a) At a time of 2 seconds, where the lines intersect, do the displacements of the two objects from their initial positions have the same magnitude? Briefly explain your answer.

(b) At a time of 2 seconds, where the lines intersect, do the velocities of the two objects have the same magnitude? Briefly explain your answer.

(c) At a time of 2 seconds, where the lines intersect, which object, if either, has a net force with a greater magnitude exerted on it? If the net force has the same magnitude for both objects, indicate this explicitly

(d) In a clear, coherent paragraph-length response, explain your response to part (c). Be sure to reference and compare the graphed information for both objects A and B.

Answer 1

Answer:

After a little online search, I've found the graph of this question, the graph can be seen below.

a) The displacement is defined as the distance between the final position and the initial position.

In the graph, the vertical axis represents the distance. We also can see that both of the lines start in position 0, so at any given time, the displacement of the objects is given by the vertical position in the graph.

Thus, at t = 2 seconds, both lines have the same y-value, this means that the displacements have the same magnitude.

b) The velocity is related to the slope of the curve,

We can clearly see that the slope of graph A and the slope of gaph B are different at t = 2 seconds (graph A is steeper) then we can conclude that the velocities do not have the same magnitude.

c) By Newton's second law, we know that F = m*a

Force equals mass times acceleration.

Acceleration is the rate of change of velocity. When the position graph is a straight line, in any point of the line the slope will be the same, thus the object has always the same velocity, thus the object is not accelerated.

If we do not have a straight line (like in graph A) then the velocity is changing, then we have acceleration, then we have a force.

Then object A has a greater net force (because object B has a net force equal to 0)

d) It is already explained in point c.