# Speed, velocity & acceleration

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• Created by: Phelps
• Created on: 18-12-13 17:06
• Speed, velocity & acceleration
• Speed
• Scalar quantity (size only)
• v = Distance moved / Time taken
• SI unit = m/s
• Velocity
• Vector quantity (size and direction)
• Distance-Time Graph
• Gradient of graph increases with speed
• Speed-Time Graph
• Area under graph = distance travelled
• Acceleration
• a = change in velocity / Time
• SI unit = m/s2
• All objects near the earth fall with a constant acceleration = 10m/s
• Acceleration of free fall is NOT dependent on mass
• rate of change in velocity per unit time
• Acceleration is constant if a constant resultant force is acting
• a = v-u / t
• Acceleration is NOT constant if a varying resultant force is acting
• e.g. objects falling in air; car accelerating (air resistance increases with velocity)
• Motion of bodies falling in an uniform gravitational field
• In a Vacuum
• Velocity
• Acceleration
• With Air Resistance
• Velocity
• Acceleration