FORCES NOTES 3-1, 3-4
Force:
A net force results in a change of motion:
Unbalanced Force - when a net force changes an objects motion.
Balanced Force - Equal forces acting on one object in opposite directions.
SPEED:
Velocity:
- A force is a push or pull on an object.
- Force gives energy to an object, sometimes causing it to start or stop moving or change the direction that the object is moving.
- Measured using a spring scale or force probe.
- Units: Newtons(N)
- Net Force - The overall force acting on an object.
A net force results in a change of motion:
- The net force is the "left over" amount when all the forces are added. If it's an equal amount, then there is no net force.
- If there is a net force, the object will change its direction or velocity. This is called acceleration.
Unbalanced Force - when a net force changes an objects motion.
- People pushing a broken car.
- A game of tug-o-war.
Balanced Force - Equal forces acting on one object in opposite directions.
- The object will not move.
- Standing or sitting in a chair.
SPEED:
- Speed is the distance an object travels in one unit of time.
- Speed is a scalar quantity - shows distance over time.
- Calculating speed - divide the distance the object travels by the amount of time ti takes to travel that distance.
- Constant speed - If the speed of an object does not change.
- Light travels at a constant speed.
- Average speed - the total distance divided by the total time.
- Most objects dont move at constant speeds for very long. For example, a bicyclist may ride for 32 km, stop and take a break and then ride 12 more km.
Velocity:
- Speed in a given direction.
- Vector quantity: shows speed plus direction.
- Velocity vectors: arrows pointing toward direction object is moving.