Question

1. the activity above was changed such that students varied the type of object and measured each new objects length. this measurement of length is called the

a. independent variable
b. dependent variable
c. constant variable
d. control group

use the image below to answer questions 8 through 11.
use the following information to answer questions 8 - 11.
an air - hockey puck is currently sliding over a frictionless surface between two bumpers. each time the puck runs into a bumper it instantaneously changes direction and travels towards the other bumper. the distance between both bumpers is 4.5 meters.
question 8

1. the hockey puck has completed 7 trips across the surface, meaning it has changed its direction 6 times. which of the following correctly describes the motion of the hockey puck during those 7 trips?

a. the hockey puck has a displacement of 2.1 meters and has traveled a distance of 4.5 meters.
b. the hockey puck has a displacement of 2.1 meters and has traveled a distance of 31.5 meters.
c. the hockey puck has a displacement of 4.5 meters and has traveled a distance of 6.2 meters.
d. the hockey puck has a displacement of 4.5 meters and has traveled a distance of 31.5 meters.

Explanation:

In an experiment, the independent variable is what is changed or manipulated. The dependent variable is what is measured and is affected by the independent variable. A constant variable stays the same throughout the experiment, and a control group is used for comparison. Here, the type of object is changed and the length is measured, so length is the dependent variable. For the hockey - puck problem, displacement is the straight - line distance from the starting point to the ending point, and distance is the total path traveled. After 7 trips, the puck ends up at the opposite side (assuming it starts from one end), so displacement is 4.5 meters, and the distance traveled is 7×4.5 = 31.5 meters.

Answer:

Question 7: B. Dependent variable
Question 8: B. The hockey puck has a displacement of 4.5 meters and has traveled a distance of 31.5 meters.