Within the Gaetz Lake Sanctuary in Red Deer, Alberta, is a looped trail that is 4 km long. Suppose a person walked all the way around the looped trail in 1 h, ending where he or she started. Which statement best describes this person’s motion over this time interval?
A.The person moved with an average speed of 0 and an average velocity of
+ 4 km/h.
B.The person moved with an average speed of - 4 km/h and an average velocity of - 4 km/h.
C.The person moved with an average speed of 4 km/h and an average velocity of 0.
D.The person moved with an average speed of 4 km/h and an average velocity of + 4 km/h.
velocity is directional, while speed is not. So, (C)
D. The person moved with an average speed of 4 km/h and an average velocity of +4 km/h.
D.The person moved with an average speed of 4 km/h and an average velocity of + 4 km/h.
To determine the correct answer, let's first understand the difference between speed and velocity:
Speed is a scalar quantity that measures how fast an object is moving. It only considers the magnitude of the motion and does not take into account direction.
Velocity is a vector quantity that measures the rate at which an object changes its position. It includes both the magnitude (speed) and the direction of the motion.
Now, let's analyze the situation:
The person walked all the way around the looped trail, ending where they started. Since they ended up at the same location, their total displacement is zero. Displacement is a vector quantity that measures the change in position, considering both distance and direction.
Since the total displacement is zero, the average velocity over the entire time interval is also zero. Therefore, options A and D, which include an average velocity other than zero, can be eliminated.
Now, let's consider the average speed, which is simply the total distance traveled divided by the total time taken. The person walked the entire 4 km loop in 1 hour, so their average speed is 4 km/h.
From the remaining options, only option C includes an average speed of 4 km/h and an average velocity of 0. This means that the person's motion was at a constant speed of 4 km/h, but they did not change their position in any particular direction.
Therefore, the correct answer is C. The person moved with an average speed of 4 km/h and an average velocity of 0.