1) During a game of football, an 80 kg wide receiver runs with the ball to the right with a velocity of v1 = 7.5 m/s. He is tacked by a 100 kg defensive back, running to the left with speed v2 = -5.9 m/s. If they "stick together" after colliding, what is their combined final velocity? (Hint: Be careful with plus and minus signs.)
2) A raindrop with a radius of 1.5 mm and mass 0.014 g falls from a cloud that is at a height of 1200 m above the ground. What is its terminal speed? (Take the drag coefficient to be 0.6, and assume the drop is spherical. The density of air is 1.2 kg/m3.)