Physics – Kinematics, Projectile Motion, Free-Body
Diagrams, and Rotational Motion
Kinematics and Projectile Motion Problem Solving Steps
1. Read and Re-Read the whole problem carefully before trying to solve it.
2. What is the question asking for? What specific object is moving and in what time
interval? You can often choose the initial time to be t=0.
3. Draw a Diagram of the object with coordinate axes wherever applicable. Write down all
the given information about the object of interest. Take note of what you want to know.
You can orientate the xy coordinate system any way you choose.
4. Decide which principle of physics the object is experiencing.
5. Pick equation that solves for your unknown. Before using them, be sure they apply to
your problem. Solve using algebra techniques. If the units do not match an error was
made. Great way to check yourself.
6. Carry out numerical calculations, only round off in the final answer to the correct
number of significant figures. When carrying out computation keep track of units. An
equal sign implies the units on each side must be the same.
7. Are your results reasonable within the context of the problem?
Kinematics Example Problem
A lead ball is dropped into a lake from a diving board 6.0 [m] above the water. After entering the
water, it sinks to the bottom with a constant velocity equal to the velocity with which it hit the
water. The ball reaches the bottom 5.0 [s] after it is released. How deep is the lake?
