Gravity at Work

Gravity at Work



Topic Cluster

Newtonian Physics


Arshad Saleem Bhatti
Professor of Physics
Department of Physics
COMSATS Institute of Information Technology, Islamabad. Pakistan

Lesson Feedback


This video lesson highlights how science can be learned from daily life experiences. It emphasizes the ways in which simple laws of physics can be understood from personal observations and experiences, and in fact it demonstrates that we use these laws as if they were built into our instincts. The video also introduces Newton’s laws of motion. The title, “Gravity at Work,” comes from a fascinating example of two laborers working at a construction site in Pakistan. We all know that gravity pulls everything thrown upward back to the surface of the ground. A projectile thrown upward with some angle makes a trajectory similar to a parabola. When the projectile attains the maximum height, it becomes weightless for an instant, and this point of maximum height depends on the angle of throw. In this lesson, Newtonian equations of motion are used to determine the velocities and height achieved by the projectile in a very simple and basic manner. This video also poses a question on the estimation and accuracy of the throw, since workers are working without measuring any distances or angles, yet they are precise and accurate. At the end, students should be able to use Newton’s equations of motion to solve the motion of a body under gravity. Another example that can be thought about and worked out after this video module is that of Bungee jumping.

Instructor Biography

Professor Bhatti teaches solid state physics, semiconductor physics, and microfabrication at the COMSATS Institute of Information Technology, Islamabad. He obtained his PhD from Cambridge University, UK in 1995. At COMSATS, he established the Department of Physics and Device Fabrication Laboratories for teaching and research. He works in synthesis and electro-optical characterization of low dimensional systems.

Additional Online Resources

This site, sponsored by Zona Land Education in Physics and Mathematics, provides a general solution for the two dimensional motion of an object thrown in a gravitational field.

This site, Circus Physics, is sponsored by the Public Boadcasting System (PBS) and provides a video and study guide for learning about the path of a projectile in motion.

This is the accompanying study guide to the above PBS lesson.