In our experiment on free-fall, you dropped a "picket fence" through a photogate and the computer recorded the time between the leading edges of the stripes on the
picket fence breaking the beam of the photogate. From this time, you found a graph
of position x versus time t. Suppose this experiment were performed on a different
planet, Planet X, resulting in the graph shown. What is the acceleration due to
gravity on Planet X? (Choose the best answer.)
Position vs. Time
0.35
y = 0.8478x2 + 0.418x + 1E-05
0.3
0.25
E 0.2
x 0.15
0.1
0.05
0
0
0.1
0.2
0.3
0.4
0.5
t(s)

Given that the train which is heading north on the tracks takes 6 seconds to reach 60 miles per hour and completes the entire 60 mile trip in one hour, we can calculate the train's average speed and velocity over the one hour trip. Now right off the bat we know that the measurement we calculate for the train's average SPEED will be a scalar quantity as we are dealing with speed. On the other hand the measurement we calculate for the train's velocity will be a vector quantity as we are dealing with velocity and the quantity has both a magnitude and a direction. Now: we now that the train completed the entire 60 mile trip in one hour which means it is going 60 mph north, which is the velocity This velocity has both a magnitude (60 mph) and a direction (north). For the train's average speed we look at distance divided by time. The speed of the train is 60 miles per hour. The difference between speed and velocity is that speed is how fast an object is going with respect to a frame of reference versus velocity is a measure of the speed and direction of an object.