1 2500kg railroad car moving with a speed of 3 m/s is linked with a 3500 kg railroad car moving away from the first car with a speed by 1 m/s. Both are moving along a straight track. Find the speed of the two cars just after they link up. The answer is 1.83 m/s but I am confused how to solve it to get that.

Air flows upward in the wick of a lantern because of the liquid property called

1. jay fills a wagon with sand (about 20 kg) and pulls it with a rope 30 m along the beach. he holds the rope 25° above the horizontal. the rope exerts a 20-n tension force on the wagon. how much work does the rope do on the wagon?

Ahair dryer is basically a duct in which a few layers of electric resistors are placed. a small fan pulls the air in and forces it through the resistors where it is heated. air enters a 1200 w hair dryer at 100 kpa and 22°c and leaves at 47°c. the cross-sectional area of the hair dryer at the exit is 60 cm2. neglecting the power consumed by the fan and the heat losses through the walls of the hair dryer, determine (a) the volume flow rate of air at the inlet and (b) the velocity of the air at the exit.