Q. Presume you are driving on the interstate at 85 mph when you see a highway patrol car parked up ahead. You apply your brakes, decelerating at a constant rate of 4 mph/sec until you're reduced your speed to 65mph. You next maintain a constant speed of 65 mph. You pass the petrol car 15 seconds after you initially applied the brakes and are relieved that he doesn't pull out after you. How far away was the highway petrol car while you first saw it?
Q. Calculate the horizontal force that must be applied to a 1.00 kg puck to make it accelerate on a horizontal friction-free air table with same acceleration it would have if it were dropped and fell freely.