Marina conducts an experiment investigating Newton’s first law of motion by sliding several objects across a smooth floor. The time in seconds it took for each object to travel 100 centimeters is recorded in the following table.

Question

Newton’s First Law of Motion
Surface: Smooth Floor – Time in Seconds
Object Trial 1 Trial 2 Trial 3 Trial 4 Trial 5
Toy 3.1 2.9 3.0 2.9 3.1
Block 3.2 3.0 3.6 3.3 3.4
Ball 2.3 2.1 2.2 2.1 2.1
Pen 1.8 1.9 2.1 1.7 1.5
Which of the items had the fastest average speed over the five trials?

(1 point)
Responses

the Pen
the Pen

the Block
the Block

the Ball
the Ball

the Toy

Answer 1

To determine which item had the fastest average speed over the five trials, we need to calculate the average time taken for each object and then convert that into speed.

The formula for speed is: $$\text{Speed}=\frac{\text{Distance}}{\text{Time}}$$

Here, the distance is 100 centimeters for each object.

First, let's find the average time for each object:

Toy: $$\text{Average}=\frac{3.1+2.9+3.0+2.9+3.1}{5}=\frac{15.0}{5}=3.0\text{ seconds}$$

Block: $$\text{Average}=\frac{3.2+3.0+3.6+3.3+3.4}{5}=\frac{16.5}{5}=3.3\text{ seconds}$$

Ball: $$\text{Average}=\frac{2.3+2.1+2.2+2.1+2.1}{5}=\frac{10.8}{5}=2.16\text{ seconds}$$

Pen: $$\text{Average}=\frac{1.8+1.9+2.1+1.7+1.5}{5}=\frac{9.0}{5}=1.8\text{ seconds}$$

Now we'll calculate the average speed for each object:

Speed of Toy: $$\text{Speed}=\frac{100,\text{cm}}{3.0,\text{s}}\approx 33.33,\text{cm/s}$$

Speed of Block: $$\text{Speed}=\frac{100,\text{cm}}{3.3,\text{s}}\approx 30.30,\text{cm/s}$$

Speed of Ball: $$\text{Speed}=\frac{100,\text{cm}}{2.16,\text{s}}\approx 46.30,\text{cm/s}$$

Speed of Pen: $$\text{Speed}=\frac{100,\text{cm}}{1.8,\text{s}}\approx 55.56,\text{cm/s}$$

From these calculations, we find:

• Toy: 33.33 cm/s
• Block: 30.30 cm/s
• Ball: 46.30 cm/s
• Pen: 55.56 cm/s

Therefore, the item with the fastest average speed over the five trials is the Pen.