Question

lo: swbat analyze data from investigations to assess the factors that could affect an objects constant speed
dol: given a set of problems, students will analyze data from investigations to assess the factors that could affect an objects constant speed by answering at least 4 of 5 questions correctly
1
a toy car rolls 10 meters in 5 seconds on the tile floor and 10 meters in 8 seconds on the carpet
what is the cars speed on each surface, and which surface helps it maintain a constant speed better?
a. tile = 2 m/s; carpet = 1.25 m/s → tile helps maintain a constant speed better.
b. tile = 10 m/s; carpet = 8 m/s → carpet helps maintain a constant speed better.
c. tile = 2 m/s; carpet = 1.25 m/s → both surfaces give the same constant speed
d. tile = 5 m/s; carpet = 10 m/s → carpet makes the car go faster.
2
sarah and her friends are conducting an investigation about speed during their schools field day. they measured the time it took for students to run different distances. which two of the following measurements would sarah need to calculate the average speed of a runner?
a. the distance the runner covered.
b. the runners height.
c. the time taken to complete the run.
d. the runners age.
e. the runners shoe size.

Explanation:

Step1: Calculate speed for toy car

The formula for speed is \(v=\frac{d}{t}\). For the tile floor, \(d = 10\space m\) and \(t=5\space s\). So \(v_{tile}=\frac{10}{5}=2\space m/s\). For the carpet, \(d = 10\space m\) and \(t = 8\space s\). So \(v_{carpet}=\frac{10}{8}=1.25\space m/s\). A smoother surface (tile) has less friction, so it helps maintain constant speed better.

Step2: Determine what's needed for average speed

The formula for average speed is \(v_{avg}=\frac{\text{total distance}}{\text{total time}}\). So to calculate average speed, we need the distance the runner covered (to know the numerator) and the time taken to complete the run (to know the denominator). A runner's height (B), age (D), and shoe size (E) are not relevant to the calculation of speed.

Answer:

1. A. Tile = 2 m/s; Carpet = 1.25 m/s → Tile helps maintain a constant speed better.
2. A. The distance the runner covered, C. The time taken to complete the run