5. (a) The height y to which a ball thrown vertically upward with a velocity of 100 feet per second rises in x seconds is given by the formula,
In how many seconds will the ball rise to a height of 144 feet?
5. (b) Draw the graph of the equation
(College Entrance Board.)
6. Two launches race over a course of 12 miles. The first steams
miles an hour. The other has a start of 10 minutes, runs over the first half of the course with a certain speed, but increases its speed over the second half of the course by 2 miles per hour, winning the race by a minute. What is the speed of the second launch? Explain the meaning of the negative answer. (Sheffield Scientific School.)