Projectile Motion

Objects tend to exhibit projectile motion when dropped or thrown, since we live in a uniform gravitational field. In free fall, without resistive forces and other complications, the horizontal motion has constant velocity, while the vertical motion has constant acceleration. These perpendicular components of motion are coordinated (synchronised) yet otherwise independent. Through the energy lens, learners should appreciate how the potential energy changes in the vertical direction parallel to the field lines, and to relate speed with kinetic energy. Learners should have sufficient opportunities to make sense of various mathematical and graphical representations.

Including air resistance complicates the mathematics quite a bit, though this can be seen as an opportunity for numerical modelling – bridging data, theory, and computation.

5.1 Free fall & 5.3 Effects of air resistance

Visualising trajectories

Learning Outcomes: 

Curriculum Emphasis:

What does the motion of objects in free fall or with air resistance look like?


Visualise the trajectory of objects under free fall or with air resistance. The following resources may be useful:

These trajectories should be matched with corresponding kinematics graphs.

Modeling projectile motion

Learning Outcomes: 

Curriculum Emphasis:

How do we analyse the motion of objects in free fall or with air resistance?


Investigate the motion of objects under free fall or with air resistance. Data can be collected using video tracking and analysed to determine the forces involved. 

You may refer to the web-TLG page on modeling for guidance and general resources.

For the use of Tracker for projectile motion, the following website provides a wide range of activities:

In particular, this activity may be especially useful:

The following video provides an example of how this can be facilitated with students:

Do note that students may find difficulty in appropriately tracking motion with air resistance through air for objects with a large surface area, due to possible sideways motion. A viable alternative would be to drop ball bearings through a viscous fluid such as oil or glycerine, such as in the following video:

Applications of Kinematics Models

Learning Outcomes: 

Curriculum Emphasis:

What can an understanding of kinematics be used for?


Explore case studies of technologies that make use of kinematics directly. Students may be excited by how digital modeling in 3-D animation or games rely on basic physics.

The following (free) course from Khan Academy is a good introduction to how kinematics and dynamics are used in animation:

5.2 Gravitational potential energy in a uniform field

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