Dynamics Flashcards
What can a resultant force cause?
- Stationary object to move.
2. Moving object to stop, move faster, slow down, change direction.
What does no resultant force mean?
No resultant force doesn’t mean that there are no forces acting on the body. It means that all forces are balanced.
What is Newton’s second law?
Resultant force acting upon object is equal to product of mass and acceleration of the object; the direction of force is same as that of the object’s acceleration.
How do we find force?
Mass times acceleration.
What is the SI unit for force?
newton(N)
What is Newton’s third law of motion?
For every action, there is an equal and opposite reaction.
What is friction?
Forces that opposes motion between 2 surfaces in contact.
What does friction not depend on?
Area of contact of the surfaces.
What does the size of the frictional force depend on?
- Material in contact.
- Nature of surfaces in contact; the rougher the surface the greater the friction.
- Proportional to force pressing surfaces together. (Or weight)
What are the effects of balanced forces on a body?
- Body remains stationary.
2. Body moves with constant velocity.
How do we know when the body has balanced forces acting on it?
When resultant force is 0.
How do we know if forces acting on a body are unbalanced?
When resultant force is not 0.
What is friction independent of?
- Area of contact between surfaces.
2. Relative velocity between the 2 surfaces.
What is friction needed for?
- Prevent motion
2. Produce motion.
What are some methods of reducing friction?
- Lubricate surfaces in contact with oil or grease.
- Use ball bearings or rollers.
- Separate surfaces with cushion of air.
