Physics C Mechanics

Practice Problems: Motion Graphs

1. (easy) The graph below shows how a car moves along a straight road as a function of time. Describe (in words) what the car is doing during the experiment and what devices on the car must be utilized for the motion to occur. 2. (easy) If the time axis in question #1 was shifted upward how would that change your response to the question?

3. (moderate) By analyzing the x-t graph shown here, answer the questions below. The first segment of the graph has a width of 5 seconds and a height of 7 m. The width of the middle segment of the graph is 6 seconds. The final segment of the graph has a width of 3 seconds.

A. Create an accurate v-t graph that expresses the same motion.

B. What is the velocity of the object during the first 5 seconds?

C. What is the average velocity of the object over the entire experiment?

D. What is the average speed of the object over the entire experiment?

E. What is the average velocity during the final three seconds?

F. What is the total area under the v-t graph you created?  How does that answer correlate to the x-t graph?

4. (moderate) By analyzing the v-t graph shown here, answer the questions below. The initial velocity on the graph is 10 m/s forward.  It takes 8 seconds for the object to come to rest (momentarily.) The object moves backward for an additional 2 seconds until it reaches a final velocity of 2.5 m/s backward.

A. How far does the object move in the first 8 seconds?

B. If the initial position of the object was at x = -15 meters, what it the final position?

c. What is the acceleration of this object?

5. (moderate) If the time axis on the v-t graph in the previous question was shifted slightly upward, how would that change the magnitude of your answers?

6. (moderate) Consider the motion of the horse in the sketch below. During the first 10 seconds the horse moved with constant speed. During the next 10 seconds the horse accelerated uniformly. During the final 20 seconds the horse underwent a different uniform acceleration. Create a motion graph (position vs. time) for the horse. 7. (moderate) Solve the problem shown below. 