If humans only have three kinds of color photo-receptors, how can we see so many different colors?

1400 kg car has a speed of 27 m/s. if it takes 7 s to stop the car, what is the impulse and the average force acting on the car?

What is the rate of 12 liters of water moving through a water hose in 4.0 minutes?

1. a camcorder has a power rating of 19 watts. if the output voltage from its battery is 7 volts, what current does it use?answer units 2. a 1.5m wire carries a 6 a current when a potential difference of 57 v is applied. what is the resistance of the wire? yourunits 3. a clothes dryer uses about 2 amps of current from a 240 volt line. how much power does it use? yourunits 4.