Physics Recap Notes: Effect of forces

Physics Recap Notes:  Effect of forces

1. What might happen to an object when a force act upon it?
1. Accelerate or decelerate
2. Change direction 
3. Rotate the object
4. Change its shape and size
5. increase its momentum
2. How a force may change the motion of a body?
   A force may change the speed or the direction or both.
1. To change the speed only, we apply a force in the direction of motion.
2. To change the direction only, we apply a force that is perpendicular to the direction of motion 

Turning Effect of forces

1. What will happen to an object  that is hinged at one point and force is applied at any point a way from the hinged point?
   the object will rotate around the hinged point and the applied force is called the "turning force".  The hinged point is called the "pivot" or the "fulcrum".
2. What is meant by "the line of action of a force"?
   Is the extension of the force vector 
3. What are the factors that determine the size of the turning effect?
   1- the magnitude of the force
   2- the distance from the the line of action of the force from the pivot.
4. What is the definition of moment?
   Moment is the turning effect of a force about a pivot and it is defined as
   Moment=force*perpendicular distance from the pivot.
5. Classify moments based on direction.
   Clockwise moment: is the moment resulted by a force that turns the object around the pivot in the same clockwise direction.
   Anticlockwise moment: is the moment resulted by a force that turns the object around the pivot in the opposite direction to the clockwise direction.
6. How do we determine the direction of moment?
   
7. Define equilibrium?
   A system is said to be in equilibrium if it is not rotating on point in the system and the net forces acting on the system is zero.
8. What are the equilibrium conditions?
1. The sum of all forces in one direction is equal to the sum of all forces in the other direction.
2. The sum of all clockwise moments is equal to the sum of all anticlockwise moments at any point in the system.
9. State the principle of moments?
   The sum of all clockwise moments is equal to the sum of all anticlockwise moments at any point in the system.
10. What is meant by the support force?
    Is the force provided by the support to hold the system in equilibrium