physics yr10 Flashcards
Doppler effect
effect produced by a moving source of waves in which there is an apparent upward shift in frequency for observers towards whom the source is approaching and a downward shift in frequency from receding observer.
Velocity
speed taken to go form point A to B
Instantaneous speed
speed at any particular instant of time
Sonic motion detectors
send out pulses of ultrasound at 40kHz. Use time taken to come back to measure distance.
Old speedometer
use rotating magnet. Spins same speed as wheels, rotations create electric pulse in device connected to pointer.
new speedometer
Rotation toothed wheel disrupts stationary magnetic field. Sensor detects interruptions and turns them into pulses to computer which calculates speed using frequency.
radar guns
Instantaneous speed calculated through altered frequency of waves sent out through radio waves.
laser guns
Send out pulses of light. Average speed recorded through time taken for pulse to comeback.
digitectors
Two cables laid across road. Detects sound of moving car. Average speed is the time interval between sounds.
GPS
Radio signals from 4-32 satellites to navigate where you are. Uses Doppler effect.
acceleration
Measure of rate at which something changes speed.
Newton’s first law of motion
States object will remain at rest, or will not change its speed or direction, unless it is acted upon by an outside, unbalanced force.
inertia
Property of objects that makes them resist changes in their motion.
Law of conservation of energy
Energy is never created nor destroyed
thrust
Forward push
