Skills and Basics

The formula to calculate speed is

v -> Speed
d -> distance
t -> time

Answer explanation

The correct formula to calculate speed is v = d/t, where v represents speed, d represents distance, and t represents time. This formula shows that speed is equal to the distance traveled divided by the time taken to travel that distance.

Tags

NGSS.MS-PS3-1

The speedometer of a car measures

• average speed

• instantaneous speed

• constant speed

Answer explanation

The speedometer of a car measures the instantaneous speed, which is the speed of the car at a specific moment in time. It does not measure average speed, which is the total distance traveled divided by the time taken, nor does it measure constant speed, which is a steady, unchanging speed.

What information does the slope of a distance vs. time graph give you?

• the object's height above the ground

• how far the object has gone

• how fast the object is going

• the direction the object is moving

• if the object is going up or down a hill

Answer explanation

The slope of a distance vs. time graph represents the object's speed. A steeper slope indicates a faster speed, while a flatter slope indicates a slower speed. Therefore, the correct choice is 'how fast the object is going'.

On a distance vs. time graph, a straight line indicates that the object has a

• constant speed

• average speed

• acceleration

• deceleration

Answer explanation

In a distance vs. time graph, a straight line represents constant speed because the object is covering equal distances in equal intervals of time. The slope of the line indicates the speed, and a straight line means the slope is constant, which implies constant speed. Other options like average speed, acceleration, and deceleration are not represented by a straight line in this type of graph.

Tags

NGSS.MS-PS3-1

According to this position vs. time graph, which object is traveling the fastest?

• Small car (Red)

• Big car (Blue)

Answer explanation

According to the position vs. time graph in the question, the small car (Red) is traveling the fastest. This is because its slope is steeper compared to the big car (Blue), indicating a higher velocity or speed.

Tags

NGSS.MS-PS3-1

A flat (horizontal) line or line segment on a distance vs. time graph indicates....

• the object has changed directions

• the object is moving on a flat surface

• The object has increased speed

• the object has stopped

Answer explanation

A flat line on a distance vs. time graph indicates that the object has stopped because the distance remains constant over time. This means the object is not moving, and its speed is zero. The other options, such as changing directions, moving on a flat surface, or increasing speed, would result in different graph patterns.

On a distance vs. time graph, a line that slopes upward from left to right indicates...

• Moving farther away from start at a changing speed

• Moving closer to start at a changing speed

• Moving farther away from start at a constant speed

• Moving closer to start at a constant speed

Answer explanation

On a distance vs. time graph, a line that slopes upward from left to right indicates that the object is moving farther away from the start at a constant speed. This is because the slope represents the speed, and a constant slope means a constant speed. The upward direction shows that the distance is increasing, meaning the object is moving away from the start.

Tags

NGSS.MS-PS3-1

On this distance vs. time graph, a line that slopes downward from left to right toward the x-axis indicates...

• Moving farther away from start and slowing down

• Moving farther away from start at a constant speed

• Moving closer to start and slowing down

• Moving closer to start at a constant speed

Answer explanation

On a distance vs. time graph, a line that slopes downward from left to right toward the x-axis indicates that the object is moving closer to the starting point at a constant speed. This is because the distance from the starting point is decreasing at a steady rate as time progresses.

Tags

NGSS.MS-PS3-1

Which line segment indicates the fastest part of this object's journey?

• A-B

• B-C

• C-D

Answer explanation

The line segment C-D indicates the fastest part of the object's journey. This is because the slope of the line represents the speed, and the steeper the slope, the faster the speed. In this case, the line segment C-D has the steepest slope among the given options, indicating the highest speed.

Tags

NGSS.MS-PS3-1

Select all options that are true about segment A-B

• The object is moving in the negative direction

• The object is speeding up

• The object is moving at a constant speed

• The object is going up hill

• The object is moving in the positive direction

Answer explanation

In segment A-B, the object is moving in the positive direction, as it is going from point A to point B. The other options are not applicable to this specific segment without additional context or information.

Tags

NGSS.MS-PS3-1