AP Wednesday 22 Sep

Learning Objective: Free Body Diagram

Journal: What is a Free Body Diagram.

Notes

Force: Push or Pull between TWO objects:

 

Contact Forces:  

• Normal - (Push always & 90⁰ from surface
•   sometimes called Applied (or normal) if not from below                               (Push always & 90⁰ from surface)
• Tension -  (Pull always)
• Buoyancy  (push up)
• Friction (push against)
• Force of Air or Drag (Air Friction)

Non-contact Forces

• Gravitational Force (Pull always called Weight = Mass x Gravity)

• Magnetism  (push or pull)

• Electric  (push or pull)

 

 

 

 

 

Free Body Diagram:  Means one object free from all other things except the forces on it. ( i.e., show only the forces acting on the object)  

Draw a free-body diagram for the following situations:

• A book is at rest on a table top. A free-body diagram for this situation looks like this:
   

 

 

 

 

 

2. A girl is suspended motionless from the ceiling by two ropes at 30⁰ angles.
 

 

 

 

 

 

 

 

3. Two books on a table, one on top is 10-kg, one on the bottom is 15-kg 

 

 

 

 

 

 

 

 

 

 4. A rightward force is applied to a 15-kg book in order to move it across a desk (frictional force of 20N) with a constant velocity. Also, find the applied force

 

 

 

 

 

 

 

 

 

5. A rightward force is applied to a 15-kg book in order to move it across a desk (no friction) with a rightward acceleration of 2 m/s². Also, find the applied force.
 

 

 

 

 

 

 

 

 

6. A rightward force is applied to a 15-kg book in order to move it across a desk (frictional force of 30N) with a rightward acceleration of 2 m/s². Also, find the applied force.

 

 

 

 

 

 

 

 

 

 

7. One 5-kg object is being pulled up with an acceleration of 3m/s². Also, find the tension force.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

8.

No friction, what does the free body diagram look like? 
 
 

 

 

 
 
 

 

 

 

 

 

 

 

 

 

 

Pass back Test Ch 1-3:

Test Justification due Mon 27 Sep