Motion and Kinematics

Vector or Scalar Quantities

View Activity

Vocabulary

View Activity

Displacement Time Graph

View Activity

Discussion Starter

View Activity

Compare Graphs

View Activity

Acceleration and Velocity Vectors

View Activity

Essential Questions for Motion

1. What is a scalar/vector quantity?
2. How can we describe motion?
3. How can we calculate speed?

Kinematics and Motion Definition

Kinematics is an area of study in classical physics that deals with motion. Some people could even argue it is actually an area of Mathematics. We can describe the motion of objects by looking at the different measurable quantities such as displacement, velocity, and acceleration. Displacement is distance with a direction. Velocity, or speed, is how fast something is moving. In order to calculate the average speed you need to know two things: the distance the object has traveled and the time it has taken the object to cover that distance. Science uses the S.I. units for speed, m/s (meters per second). In everyday language, we can also describe speed in the units of mph (miles per hour) or km/h (kilometers per hour). The equation for speed is distance divided by time taken (speed = d ÷ t). Instantaneous speed is the speed at a particular moment, whereas average speed is the mean speed across a large distance. Acceleration is a measure of the rate of change of speed. Acceleration can be positive, meaning velocity is increasing, or negative, meaning velocity is decreasing.

The motion of the object can be described using charts. It is important that students are able to interpret velocity-time graphs and displacement-time graphs. In both of these graphs, time runs along the x-axis with velocity or displacement on the y-axis. For a displacement-time graph, the gradient or slope of the line indicates the direction and the speed an object is traveling. A line with zero gradient (a horizontal line) means the object is not moving. If the line curves, this indicates the object is accelerating, either negatively or positively.

There are two types of quantities in Science: vector quantities and scalar quantities. A vector quantity is a quantity that has both size and direction. Velocity is one example of a vector, where both the magnitude and the direction of the quantity are needed to calculate. Scalar quantities are only measured by magnitude. An example of a scalar quantity is time. Time has no direction, but does have magnitude.

Velocity and acceleration are both vector quantities and can be represented by an arrow. When the acceleration vector is in the same direction as the velocity vector, the object will increase in velocity in that direction. When the acceleration arrow is in the opposite direction to the velocity vector, the object’s velocity will decrease. If there is no acceleration, then the object will travel at a constant velocity; it will not increase or decrease.

More options

Copy This Storyboard

Other Motion Activity Ideas

1. Create a narrative storyboard showing one's motion throughout the day. Make a displacement-time graph to accompany it.
2. Plan an investigation into velocity or displacement using Storyboard That investigation planning resources.
3. Compare different scalar and vector pairs, like velocity and speed, in a T-Chart.