Conceptual Physics Questions & Answers

Conceptual Physics Questions & Answers A 1000 kg car moving at 10 m/s brakes to a stop in 5 s. The average braking force is - CORRECT ANSWER- 2000 N A 2 kg mass has 40 J of PE with respect to the ground. Approximately how high is it above the ground? - CORRECT ANSWER- 2 m A 4 kg ball has a momentum of 12 kg m/s. What is the balls speed? - CORRECT ANSWER- 8 m/s A 5000 kg freight car runs into a 10,000 kg freight car at rest. They couple upon collision and move with a speed of 2 m/s. What was the initial speed of the 5000 kg car? - CORRECT ANSWER- 6 m/s A car has a mass of 1000 kg and accelerates at 2 meters per second. What is the magnitude of the net force on the car? - CORRECT ANSWER- 2000 N A car maintains a constant velocity of 100 km/hr for 10 s. During this time interval it's acceleration is... - CORRECT ANSWER- zero A car moving at 50 km/hr skids 20 m with locked brakes. How far will the car skid with locked brakes if it were traveling at 150 km/hr? - CORRECT ANSWER- 180 m A freight train rolls along a track with considerable momentum. If it rolls at the same speed but has twice as much mass, it's momentum is.... - CORRECT ANSWER- doubled A kilogram is a measure of an object's.... - CORRECT ANSWER- mass A machine puts out 100 W of power for every 1000 W put into it. The efficiency of the machine is - CORRECT ANSWER- 10%