# Forces and motion/ movement

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• Created by: Jasminea
• Created on: 06-02-14 16:50
• Forces and motion/ movement
• Mass and weight
• MASS NEVER CHANGES
• Newton's laws of motion
• 1st law
• If the total force on an object is 0, or all the forces balance out to give zero then the object is still or moving at constant velocity
• Example: Spacecraft only needs fuel to escape the atmosphere... zero force 4 day trip to the moon at constant velocity
• Hockey, curling, parachitist
• 2nd law
• The total force acting on an object is directly proportional to it's acceleration in m/s/s. This is shown by the straight line graph on the air track experiment. The constant of proportion is the mass of the car.
• F = M x A This is for sideways motion
• F is the total force, you must find this by adding or subtracting forces before using the equation
• W = M x G. this is for falling objects (G is acceleration)
• Moon
• On the moon a hammer and feather will hit the ground at the same time because there's no air, air resistance
• Velocity is always changing (direction)
• Car
• thinking distance
• affected by
• speed
• tiredness
• poor night vision
• Phones/eating
• drugs/alcohol
• Braking distance
• affected by
• mass of vehicle
• Weather conditions
• Conditions of brakes
• Speed
• Total stopping distance = Thinking distance + breaking distance
• Parachutist
• As the skydiver first jumps out there's only weight on her and it's her strongest acceleration
• After a while she speeds up, this causes air resistance
• When air resistance = the weight force = 0 so acceleration = 0. velocity is constant, terminal velocity
• The parachute opens and this causes large area and large air resistance. This causes decelleration
• Her speed drops to a new slower terminal velocity
• She slowly drops to the ground
• Total force = W-A
• If the total force on an object is 0, or all the forces balance out to give zero then the object is still or moving at constant velocity
• Example: Spacecraft only needs fuel to escape the atmosphere... zero force 4 day trip to the moon at constant velocity
• Hockey, curling, parachitist
• A = W/M
• Speed
• Object moving at a constant speed you can use Distance = speed x time
• Velocity
• speed in a particular direction
• movement of a straight line
• Object moving at a constant speed you can use Distance = speed x time
• Graphs
• reversing, slowing, going back
• Slowing down
• Still/ stationary
• Speeding up or accelerating
• velocity time
• gradient of the graph = acceleration
• D = V x T
• D = area under the v-t graph
• Acceleration due to gravity
• If there's no air resistance. all objects fall at the same rate of acceleration,g.   G = 10m/s/s
• To convert mass and weight. M x 10 = W