Presentation on theme: "September 10 AP physics. Two forces act on a 6.00-kg object. One of the forces is 10.0 N. If the object accelerates at 2.00 m/s 2, what is the greatest."— Presentation transcript:
September 10 AP physics
Two forces act on a 6.00-kg object. One of the forces is 10.0 N. If the object accelerates at 2.00 m/s 2, what is the greatest possible magnitude of the other force? a. 1.0 N b. 2.0 N c N d N
Objective: To understand: –Forces and pulleys Free body diagrams Free body diagrams Sum of the forces Sum of the forces Tension Tension Acceleration Acceleration Success Criteria Be able to solve pulley problems
Pulley system Set up #1: Equal masses: Draw a diagram: Examine the pulley system. –What do you notice?
Set up #2: Δm=50g –What do you notice?
Set up #3: Δm=100g –What do you notice?
Set up #4: Δm=50g total mass increased –What do you notice?
What can we say about pulleys?
Forces and pulleys Pulley rules: Pulleys only change the direction of the forces. Pulleys are frictionless The do not add any force to the system
Strings dont stretch The acceleration of one body is the same as the other body only negative Strings only pull The direction of the force is always away from the object. Strings have no mass.
Steps to solve a pulley problem: 1.Draw a free body diagram of each mass. 2.Sum the forces on each body separately 3.Solve for acceleration of each body. 4.Set the two accelerations equal and opposite. 5.Solve for Tension 6.Re-substitute to get acceleration
m 1 =4 kg m 2 =8 kg What is the tension? What is the acceleration?
Solve for Tension and acceleration 50 kg 35 kg
Out: m 1 =4.5kg Draw a free body diagram of each mass: What is the tension in the string? What is the acceleration of the system? m 2 =1.5kg