SUBJECT: ASTRONOMY -- TOPIC: Time Dilation Find the time interval measured by your stationary watch if your friend’s watch measures 1.0 year while she is traveling at 0.87c aboard a futuristic interstellar rocket.

Consider a system to be two train cars traveling toward each other. what is the total momentum of the system before the train cars collide?   kg • what must the total momentum of the system be after the train cars collide?   kg •  

Aball is thrown horizontally from a cliff at 8m/s .in what direction is the ball moving 2s later?

You are driving to the grocery store at 20 m/s. you are 110m from an intersection when the traffic light turns red. assume that your reaction time is 0.50s and that your car brakes with constant acceleration. how far are you from the intersection when you begin to apply the brakes? what acceleration will bring you to rest right at the intersection? how long does it take you to stop after the light changes? the known values: vi=20m/s xi=110m t=.50s vf=0m/s xf=0m a=?