The first thing you study (in the study of motion) is the relationship between position, velocity and acceleration. In the study of forces we begin to look into the reason for those constant accelerations.

Forces make masses accelerate. Strictly speaking unbalanced forces make masses accelerate. This basic law is stated F = ma, where F is understood as an unbalanced force. Constant forces produce constant accelerations, the only kind of accelerations we know how to handle at this point. The several problems in this section illustrate some simple techniques for solving force problems with friction.

In force problems, a force is related to an acceleration through F = ma and then the kinematic equations are used to determine velocities and positions.

More complete discussions of force problems including more worked problems are contained in the two books How to Solve Physics Problemsand Physics for the Utterly Confused. Click on the appropriate icon to go directly to the book at the online bookstore.

Force (without friction) problems are listed below. Problems with the "T" prefix are those where the problem is stated and you can work on it before going on to the answer.

• TFrc03 Force on a tennis ball
• Tutorial on Atwood's Machine
• Frc11 Atwood's machine
• Frc21 Single incline plane
• Frc22 Double incline plane
• TFrc23 Single incline plane #2
• Frc31 Three mass problem
• TFrc33 Tension in cords between three blocks
• TFrc41 Boat tied in a "U" shaped dock
• TFrc51 Force between one block pushing another