Module 3 Lesson 5

Module 3—Effects of Force on Velocity

Lesson 5—Solving Net Force Problems

Get Focused

A photograph shows the front-end of a ship as it prepares to enter the Panama Canal. Railway tracks are located on both sides of the canal.

This is a photo taken from one of the upper decks of a cruise ship that is about to enter the Panama Canal. This canal is a technological solution for moving a ship from the Atlantic Ocean to the Pacific Ocean, through the Central American country of Panama. The canal works by passing boats through a series of locks, which raise and lower the boats through a vertical distance of 26 m between the oceans.

Constructing this canal was one of the most difficult engineering projects ever undertaken. It opened in 1914, after an estimated 27 500 workers died during the construction. By 2002, nearly 800 000 ships had used the canal. In 2005 alone, 200 million tonnes of cargo passed through it.

Using the canal is not cheap: In 2006, the container ship Maersk Dellys paid $249 165 for passage.

In contrast, an American adventurer by the name of Richard Halliburton paid $0.36 to swim the canal in 1928. The average cost to pass through the canal is around $54 000.

Large ships do not use their engines to pass through the canal. In the photograph, notice the rail tracks on either side of the canal passageway. Tug locomotives are along these tracks. Using a cable, a ship is attached to a tug locomotive on each side of the canal. The locomotives pull the ship straight through each of the locks in the canal. Two locomotives, one on each side, are used to do this. If the tug locomotives are positioned on either side of the boat, how can they pull the ship straight forward through the canal? How do they avoid having the tug locomotives pull the ship into the side of the canal?

In this lesson and the associated labs, you will learn to apply Newton’s second law and free-body diagram analysis to solve linear (one-dimensional) and non-linear (two-dimensional) net-force problems.

This lesson is where you bring Newton’s laws and free-body diagrams together.

As you work through this lesson, keep this question in mind:

How do free-body diagrams, vector analyses, and Newton's second law help solve moving-object problems?

Module 3: Lesson 5 Assignments

Your teacher-marked Module 3: Lesson 5 Assignment requires you to submit a response to the following:

Try This—TR 1, TR 2, TR 3, TR 4, and TR 5
Lab—LAB 1, LAB 2, LAB 3, LAB 4, LAB 5, and LAB 6

You must decide what to do with the questions that are not marked by the teacher.

Remember that these questions provide you with the practice and feedback that you need to successfully complete this course. You should respond to all the questions and place those answers in your course folder.