Forces
- Created by: Jo Wells
- Created on: 27-12-12 14:01
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- Forces
- Weight, Mass & Gravity
- Weight = Mass X Gravitational Field Strength
- W = m X g
- Gravity = makes things ACCELERATE towards ground & gives everything WEIGHT
- Weight (N) = a force
- Mass (Kg) = NOT a force
- Weight = caused by pull of gravitational force
- Mass = amount of 'stuff' in an object
- Weight = Mass X Gravitational Field Strength
- Resultant Force
- = Overall force on something
- e.g. a teapot = gravity acting downwards (10N), causing a reactant force acting upwards (10N) (keeping object stationary)
- Decides MOTION of object
- Whether it will ACCELERATE, DECELERATE or stay at a STEADY SPEED
- Means a CHANGE in VELOCITY
- e.g. moving car = driving force 1000N left, with air resistance 600N right = 400N (left)
- = Overall force on something
- & Acceleration
- If resultant force on a stationary object = ZERO, object will STAY stationary
- If there is NO resultant force on a moving object, it'll carry on at the SAME velocity (steady)
- If there is a NON-ZERO resultant force, object will ACCELERATE in direction of force
- starting, stopping, speeding up, slowing down & changing direction
- Resultant force (N) = mass (Kg) X acceleration (m/s squared)
- F = m X a
- Reaction forces = EQUAL & OPPOSITE
- Frictional force
- Friction slows things down
- Acts in opposite direction to movement
- DRAG from fluids (air or liquid)
- Reduce drag by STREAMLINING
- Drag increases as speed increases
- Friction slows things down
- Terminal velocity
- Objects falling through fluids reach a terminal velocity
- At start, gravity = much more than frictional force, so they ACCELERATE
- As speed increases, friction increases = gradually reduces acceleration until frictional force = accelerating force
- = its maximum speed or TERMINAL VELOCITY
- As speed increases, friction increases = gradually reduces acceleration until frictional force = accelerating force
- At start, gravity = much more than frictional force, so they ACCELERATE
- Terminal velocity of falling objects depends on SHAPE & AREA
- Objects falling through fluids reach a terminal velocity
- Weight, Mass & Gravity
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