Forces Force n is a push or a
- Slides: 13
Forces
Force n is a push or a pull. n a force is described by its strength and by the direction in which it acts. n The strength of a force is measured in the SI unit called the newton (N).
Balanced forces n Balanced Forces-Equal forces acting on one object in opposite directions. n Balanced forces acting on an object do not change the object’s motion. n When equal forces are exerted in opposite directions, the net force is zero. forces cancel out.
Unbalanced Forces n Forces that produce a nonzero net force, which changes an object’s motion. n cause an object to start moving, stop moving, or change direction. n Unbalanced forces acting on an object result in a net force and cause a change in the object’s motion.
Net Force When the two people push the box in opposite directions, the net force on the box is the difference between their individual forces. n The overall force on an object when all the individual forces acting on it are added together n The net force determines whether an object moves and also in which direction it moves. Net Force Example n
Friction The force that one surface exerts on another when the two surfaces rub against each other. n In general, smooth surfaces produce less friction than rough surfaces. The strength of the force of friction depends on two factors: how hard the surfaces push together and the types of surfaces involved. Friction n
Types of Friction n Sliding friction- Friction that occurs when one solid surface slides over another. n Rolling friction- Friction that occurs when an object rolls over a surface. n Fluid friction- Friction that occurs as an object moves through a fluid.
Newton’s laws n Newton’s first law of motion- states that an object at rest will remain at rest, and an object moving at a constant velocity will continue moving at a constant velocity, unless it is acted upon by an unbalanced force. Inertia-The tendency of an object to resist any change in its motion. ( depends on mass) ie. friction
Newton’s Laws n Newton’s second law of motionacceleration depends on the object’s mass and on the net force acting on the object. n Newton’s third law of motion- states that if one object exerts a force on another object, then the second object exerts a force of equal strength in the opposite direction on the first object. Action-Reaction forces
Gravity n The force that pulls objects toward each other. n Two factors affect the gravitational attraction between objects: mass and distance. – The more mass an object has, the greater its gravitational force. – The farther apart two objects are, the lesser the gravitational force between them.
Center of Mass n The center of gravity (mass)- is the point where all the weight of the object can be considered to be concentrated. n To balance an object ( see saw) you would need to find the center of mass
Air and Gravity n Free Fall- The motion of a falling object when the only force acting on it is gravity. n Air resistance- The fluid friction experienced by objects falling through the air. n Projectile- An object that is thrown.
Weight v. Mass n Weight- The force of gravity on an object at the surface of a planet. n Mass- Amount of matter in an object
- Push hard push fast fully recoil
- Push hard push fast fully recoil
- Shamiel salie
- Push hard push fast fully recoil
- Push hard push fast fully recoil
- Push hard push fast fully recoil
- Any push or pull
- Backbone of a reciprocating engine
- Magnetic force push or pull
- Amy uses 20n of force to push a lawn mower 10 meters
- Is gravitational force a push or pull
- Technology push force
- Example of market pull force
- The forces shown above are pushing/pulling forces