Atwood's Machine Lab?????

Objectives: 

1. Ask questions about how the factors of this lab will make a system move

2. Apply the laws of motion to the Atwood's Machine

Key Terms:

• inertia
• equilibrium 
• disequilibrium 
• velocity
• acceleration

Pre-Lab Discussion

What are the laws of motion? What does each law state?

The laws of motion refer to Newton's laws of motion. These laws describe the relationship between an object, the forces acting upon them, and the motion they perform in response to these forces. The first law describes inertia. The second law is the relationship between acceleration, mass, and force. The third law states describes equal and opposite physical reactions. 

When specifically discussing Newton's First Law, this law states that if the net force on an object is zero, then the object is at rest or moves with a constant speed with no change in its direction. 

What We Used:

• stand
• clamp
• PhotoGate
• pulley wheel
• two 50g hook weights
• various weights

Video: Change in Force

Change in Force - Constant Velocity

Change in Mass - Acceleration

Essential Questions: 

1. What are the variables that determine a system's state of motion (constant velocity vs. constant acceleration)?

The variables the determine a system's state of motion (constant velocity vs. constant acceleration) are FORCE and MASS. 

2. What happens when the total mass of a system is kept constant, but the net force is varied?

When the total mass of a system is kept constant and the net force is varied, the system experiences an increase in acceleration. This principle adheres to Newton's Second Law, which states that an object will accelerate if the net force does not equal zero. As long as you have constant mass, acceleration will increase with force. These two factors are proportional, meaning if force is doubled acceleration is doubled. This can be expressed in the equation:

a = F/m

Let a = acceleration

Let f= force

Let m = mass

This equation can be manipulated in to:

F = am

and

m = F/a

3. What happens when the net force on a system is kept constant, but the total mass is varied?

When the net force on a system is kept constant, but the total mass is varied, the acceleration of the system decreases. The principle also applies to Newton's Second Law, which states that an object will decelerate if the net force is 0 but the mass increases. Similarly to question two, this is due to the relationship between acceleration, force, and mass.