Displacement and Velocity
Ms. Woods leaves her room, walks up the stairs to the office, and returns to her classroom 8 minutes later. What is Ms. Woods displacement over the entire time interval?
0m
Given a graph of position vs. time, how would you find where an object is at rest?
At rest means v= 0m/s, so you would look for where the slope is equal to 0, or any flat segments.
An object starts from rest and speeds up to 8m/s in 3.5 seconds. Calculate the acceleration of the object.
+2.2 m/s2
What are the units of time?
seconds
What does it mean when an object is "at rest" or "stopped"?
The object has a velocity of 0m/s.
Calculate the displacement given the following movements:
9m E
17m E
6m W
12m W
+8m
Given a graph of position vs. time, how would you find the displacement of an object between 2 time intervals?
You would find the position of the object at both times by reading off the graph, and you would subtract the final position - initial position.
An airplane on the runway moves 840m, accelerating from rest to 65m/s. What is the acceleration of the airplane?
+2.51 m/s2
What are the units of displacement?
m
An object is thrown upward with a speed of 13 m/s. What is the velocity of the object when it comes back down?
-13 m/s
A soccer ball is kicked 17m North and then is kicked back 6m South. Calculate the displacement of the ball and report your answer in centimeters.
+1100m
Given a graph of velocity v. time, how would you find where the object is at rest?
At rest means v = 0m/s, so you would read where the graph hits the x axis or 0m/s.
An object dropped on Earth reaches a final speed of -97m/s some time later. How much time does it take to reach this speed?
9.88s
What are the units of velocity?
m/s
An object is thrown upward or falls downward on Earth. What can be implied about this object, in terms of acceleration?
a = -9.81 m/s2
A gazelle runs 7m North, 14m North, stops, and then runs 32m South. This entire motion happens over 20 seconds. Calculate the average velocity of the gazelle.
-0.55 m/s
Given a graph of acceleration vs. time, how would you determine where an object has a constant velocity?
Constant velocity means a = 0. So, you would look where the graph hits 0.
Calculate the acceleration due to gravity on a planet given that an object thrown downward at 8m/s from a height of 30m will reach the ground in 2 seconds.
-7 m/s2
What are the units of speed?
m/s
An object is dropped from a cliff. What is implied by the word "dropped"?
Vi = 0 m/s
+1.57 m/s
Given a graph of acceleration vs. time, how would you calculate the change in velocity of an object over a time interval?
Take area under the curve.
A student stands on the cafeteria table, 2.4m above the ground. They throw a sandwich straight upwards at 4m/s. How long does it take the sandwich to reach the ground?
1.22s
What are the units of acceleration?
m/s2
What can you imply if an object reaches its maximum height?
The object has a velocity of 0 m/s at that point.