Chapter 8.1, Problem 9E

A rocket is rising at a constant speed of 5 mi/s. A person is filming from their car on a straight road at a speed of 13/12 mi/s. When the car passes directly under the rocket, the rocket is 3 miles above the car. How fast is the distance between the car and the rocketincreasing 2 seconds later? (Answer: 5.1 mi/s)

A police car is parked 50 feet due north of a stop sign on straight road. A red car is travelling towards the stop sign from a point 160 feet due east on the road. The police radar reads that the distance between the police car and the red car is decreasing at a rate of 90 feet per second. How fast is the red car actually traveling along the road? The actual speed (along the road) of the red car is (Note: Think right triangle.) (Enter your answer as a decimal number rounded to 2 places.) feet per second

A hot-air balloon rises straight up at a constant speed of 20 feet/sec. An observer stands 200 feet away from the launching point. How fast is the distance between the hot-air balloon and the observer changing after 90 seconds? 20ft/s 200 ft