# Physics P3.2 (Using Physics to make things work)

Mindmap on GCSE Physics Unit P3 sub-unit 2.

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• Created by: Ethan
• Created on: 19-03-13 21:01
• Physics P3 U2
• Moments
• Moment = The turning effect of a force
• Moment = Force x perpendicular distance from pivot
• Nm = N x m
• Centre of Mass
• All mass is thought to be concN at one point
• Symmetrical object: COM along axis of symmetry
• If there are more than 1, COM is where they meet
• Stability
• Objects Line of Action of weight passes through its COM straight down towards the ground
• When LOA of the weight goes outside the base of an object
• There will be a  resultant moment
• Object will topple over
• How to improve stability
• Make the base of object wider
• This means it has further to *** before LOA of weight is outside base
• Lower the COM
• Lower the COM
• Hydraulics
• Pressure = force/area
• Pressure is given in Pa or N/m^2
• Hydraulic Pressure Systems
• Liquids are virtually incompressible
• Forces exerted at one point in the liquid will be transmitted at other points
• Pressure acts equally in all directions
• Forces exerted at one point in the liquid will be transmitted at other points
• Force Multipliers
• Hydraulic Pressure Systems
• Liquids are virtually incompressible
• Pressure acts equally in all directions
• Force Multipliers
• Circular Motion
• Centripetal Acceleration
• Object moving in a circle
• Constantly changing direction
• Constantly  changing  velocity
• Therefore it is continually accelerating
• Centripetal Force
• Object only accelerates when a resultant force is present
• Centripetal Acceleration
• Object moving in a circle
• Constantly changing direction
• Constantly  changing  velocity
• Therefore it is continually accelerating
• If this stops..
• Object will continue in a straight line at a tangent to the circle
• Pendulums
• Equilibrium position is where the pendulum is not moving
• Simple Pendulum
• Mass called a blob
• Mass suspended with a thin string from a fixed point
• Occilations
• Amplitude of an occilation is: distance from equilibrium position to highest point
• Time period is time taken for one full occilation
• Full oscillation = amplitude to other side and back
• Depends ONLY upon length of pendulum
• Longer pendulum = longer time
• Frequency = no. of occilations per second
• Moment = Force x perpendicular distance from pivot
• Nm = N x m