Vectors vs. scalars
Speed is what kind of quantity?
What is a scalar quantity.
I have two displacement vectors. Vector A has a magnitude of 8m in the positive direction, while Vector B has a magnitude of 3m in the negative direction. What is A+B?
What is a vector with a magnitude of 5m in the positive direction.
What is represented by the slope of a position vs. time graph?
The velocity!
During my AP training, I airdrop tablets of stone with the AP Physics 1 equations onto the green space of EABH for my AP students. What is the horizontal velocity of the tablets with respect to me?
0 m/s
What two qualities do vectors have?
What is both magnitude and direction.
Velocity vector C and velocity vector D both have the magnitude and direction of -10m/s. What is C-D?
What is -20m/s.
André, amazingly, runs at a perfectly constant velocity of 10m/s for 100m. If I plotted his v vs. t graph, what would it look like?
A flat line at 10m/s between t=1 and t=10 (Ok if they just say a flat line at 10)
On the road to Casabranca, my impatient Uber driver passed a truck very closely on the highway. The speed of the car was 100km/hour, while the truck was going 80km/hour. From my perspective in the car, how fast was the truck going?
-20km/h
Laura, even more amazingly, accelerates at a perfect acceleration of 1m/s/s, starting at 5m/s, for 10s. After plotting a v vs. t graph for her run, how would I calculate her displacement? (Draw on your table)
1) Find the area under the curve (OK)
2) Multiply the her time by her final velocity and divide by 2 (The velocity graph would make a triangle and A=1/2bh, base=time and h=velocity in this case.)
On the road to Casabranca, my impatient Uber driver passed a truck very closely on the highway. The speed of the car was 100km/hour, while the truck was going 80km/hour. From the perspective of the truck driver, how fast was the Uber car going?
20km/h
Density is what kind of quantity?
Scalar quantity
I am walking on a moving sidewalk in the airport. The sidewalk has velocity vs and I am walking with velocity vm. What would I do to calculate my velocity with respect to the ground?
I would add the magnitudes of vs and vm.
A velocity vs. time graph is linear with a slope of -2. Draw this on your table to help you visualize. What would the acceleration vs. time graph look like?
It would look like a flat line at a=-2.
A boat is moving in a river which is flowing at velocity v=vriver. The boat moves towards the shore perpendicular to the flow of the river at v=vA. What is the velocity of the boat relative to someone standing on the shore?
vA in the direction of flow in the river.
Snap, crackle, and pop are what kinds of quantities?
What is vector quantities
I have two displacement vectors. Vector A has a magnitude of 8m west, while Vector B has a magnitude of 3m east. Rank the following quantities from most positive to most negative: A+B, B-A, A-B
(Largest, or most postive) B-A, A+B, A-B (Most negative)
Two curves representing the motion of two objects are graphed on an x vs. t graph. The two curves intersect at t=1 before diverging. Draw this on your table. Which of the following is true?
-The instantaneous velocity of the objects are the same at time t=1.
-The average velocity of the objects are the same at t=1.
-Both are true
-Neither are true.
Only the average velocities are the same, because vavg.=change in x/t, and if they intersect at time t, change in x are the same, and t is the same. Therefore, vavg. must also be the same.
A boat is moving in a river which is flowing at velocity v=vriver. The boat moves towards the shore perpendicular to the flow of the river at v=vA. What is the velocity of the boat relative to the ground?