posted by kim on .
1. A 4.0 N force acts for 3 seconds on an object. The force suddenly increases to 15 N and acts for one more second. What impulse was imparted by these forces to the object?
2. A railroad freight car, mass 15,000 kg, is allowed to coast along a level track at a speed of 2 m/s. It collides and couples with a 50,000 kg second car, initially at rest and with brakes released. What is the speed of the two cars after coupling?
3. Lonnie pictches a baseball of mass .2 kg. The ball arrives at home plate with a speed of 40 m/s and is batted straight back to Lonnie with a return speed of 60 m/s. If the bat is in contact with the ball for .050 s, what is the impulse experienced by the ball?
4. Alex throws a .15 kg rubber ball down onto a steel plate. The ball's speed just before the impact 6.5 m/s, and just after is 3.5 m/s. What is the change in the magnitude of the balls momentum??
ANY HELP WILL BE APPRECIATED.Thanks!
duplicate post. Same answer