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Balanced & Unbalanced Forces

Forces Instant Replay Forces Instant Replay Go through the PowerPoint and take detailed notes. Page titles should be sub headings within your notes.

Newton’s Law of Motion says: “In order to move an object with mass, you need to apply a force” The greater the mass = The greater inertia => more force is needed

Force What is force? –Push or Pull It’s what causes “things” to accelerate 1000 kg

Balanced vs. Unbalanced Forces If all forces are balanced there is no acceleration in any direction. –(Either Zero Motion or Constant Velocity) If one force is greater than the opposing force we get acceleration in a direction.

Balanced Forces (Balanced Forces = No Acceleration) 5 N Equal Pushing Object Notice that all the forces are equally pointed in the opposite direction. Hence they balance each other – or cancel each other. Forces may cancel each other and produce a Net Force of 0!

Gravity pulls down on you… The ground pushes back up… THIS KEEPS YOU WHERE YOU ARE! If these football players push on each other equally as hard, will either one move? Gravity pulls down Ground pushes up Balanced Forces Example (Balanced Forces = No Acceleration)

5 N Equal Pushing Equal Pulling Forces may cancel each other and produce No Acceleration! Balanced Forces Example (Balanced Forces = No Acceleration)

Unbalanced Forces Cause Acceleration Adding Forces Subtracting Forces

Adding Forces Two forces in the same direction are added together to produce a net force. –Positive Acceleration occurs (Speed up) 5 N = 10 N

Unbalanced Forces Causes Acceleration Adding Forces 5 N Object 5 N Notice that all the forces are pointed in the same direction. Hence they add together.

Subtracting Forces When forces are in opposite directions you subtract to produce a net force that will move in the direction of the larger force. –Negative Acceleration occurs (Slow Down) 10 N 5 N = 5 N

Unbalanced Forces Causes Acceleration Subtracting Forces 5 N Object 20 N Notice that the forces are unequal and pointed in the opposite direction. Hence they are unbalanced and in opposition to each other – or one partially cancels the other. Net Force of 15N to the Right

Balanced Forces Balanced Push i.e. Pushing a Car No Change in Motion Balanced Pull i.e. Tug-o-war No Change in Motion 10N

Un-Balanced Forces Additive Un-Balanced Same Direction so you ADD Moves 20 N to the Right. Subtractive Un-Balanced Opposite Direction So you SUBTRACT Moves 10 N to the right 10N 20N10N