Acar and truck are both travelling with a constant speed of 20m/s. the car is 10m behind the truck. the truck driver suddenly applies his brakes ,causing the truck to decelerate at the constant rate of 2m/s. two second later the driver of the car applies his brakes and just manages toavoid a rear end collision. determine the constant rate at which the car decelerated.

The drive decelerated at a speed of 4m/s

The truck already was 6 meters away from the car when they car started to decelerate. The truck is still decelerating at 2m/s. The car has 3 seconds to stop. So the car would stop at 2m/s but the truck is also stopping at 2m/s so you have to add that on to get 4m/s

vapour or gas assuming atmospheriv pressure

luster is not a good characteristic to use by itself because luster is the property of minerals that indicates how much the surface of a mineral reflects light. the luster of a mineral is affected by the brilliance of the light used to observe the mineral surface.