01. Car 1 was sitting at rest when it was hit from the rear by car 2 of identical mass. Both
cars had their breaks on and they skidded together 6 m in the original direction of motion.
If the stopping force is ~ 0.7  (combined weight of the cars) , i. e.,  = 0.7, find the
approximate speed of car 2 just before the collision took place. [18.14 m/s

Aballet student who learns with the of his instructor is demonstrating learning.

Air is contained in a variable-load piston-cylinder device equipped with a paddle wheel. initially, air is at 400 kpa and 17°c. the paddle wheel is now turned by an external electric motor until 75 kj/kg of work has been transferred to air. during this process, heat is transferred to maintain a constant air temperature while allowing the gas volume to triple. calculate the required amount of heat transfer in kj/kg.

Aball is thrown from the top of a building with an initial velocity of 21.9 m/s straight upward, at an initial height of 51.6 m above the ground. the ball just misses the edge of the roof on its way down, as shown in the figure. (a) determine the time needed for the ball to reach its maximum height. (b) determine the maximum height. (c) determine the time needed for the ball to return to the height from which it was thrown, and the velocity of the ball at that instant. (d) determine the time needed for the ball to reach the ground. (e) determine the velocity and position of the ball at t = 5.35 s.