1)The equation y=−4.9x2+8.82x+1.96 represents the height of the trajectory of a ball x seconds after it was released. The solutions to 0=−4.9x2+8.82x+1.96 are x=−0.2 and x=2. Which of these solutions represents the time it takes the ball to hit the ground?(1 point)
a) both x=−0.2 and x=2
b) x=−0.2
c) x=2
d) Neither of the solutions represents the correct time.
2) The equation y=−4.9x^2+19.5x+1.75 represents the height of the trajectory of a ball x seconds after it was released. At what time is the ball 10 meters above the ground?(1 point)
a) The ball never is never 10 meters above the ground.
b) approximately 0.5 seconds and 3.5 seconds
c) approximately 3.5 seconds
d) approximately 0.5 seconds
A baseball player throws a baseball directly upward into the air. The height of the ball is given by the equation y=−4.9x^2+89.5x+1.75 where y is the height in meters and x is the time in seconds. Is this equation a reasonable model for the ball's trajectory? Explain(1 point)
a) No, the initial height is 1.75 meters, which is much taller than any person.
b) No, the equation does not match the model for projectile motion.
c) No, the initial velocity would be 89.5 meters per second. This is approximately 200 miles per hour, which is faster than any human can throw a baseball.
d) Yes, the equation matches the model for projectile motion, so it is a reasonable model for the ball's trajectory.
The equation y=−16x2+275 models the height of a projectile where y is the height in meters and x is the time in seconds. Which of the following situations is the real-world scenario that is best modeled by the given equation?(1 point)
a) A ball being dropped from shoulder height.
b) A child tossing a ball into the air.
c) A stone being dropped off of the edge of a cliff.
d) A tennis ball being launched into the air by a tennis racket.