# Thread: Parametric equations

1. ## Parametric equations

Consider a projectile launched at a height h feet above the ground and at an angle θ to the horizontal. If the initial velocity vo feet per second, the path of the projectile is modled by the parametric equations:
x= (vo*cosθ)t and y=h+(vo*sinθ)t-16t^2

The center field fence in a ballpark is 10ft high and 400 ft away from home plate. The ball is hit 3 feet above the ground. It leaves the bat at an angle of θ degrees with the horizontal speed of 100 miles per hour.

A) write a set of parametric equations for the path of the ball.
B) graph the path of the ball when θ = 15 Is the hit a home run?
C) find the minimum angle at which the ball must leave the bat in order for the hit to be a home run.

I have no idea where to start.

2. Originally Posted by jazz20
Consider a projectile launched at a height h feet above the ground and at an angle θ to the horizontal. If the initial velocity vo feet per second, the path of the projectile is modled by the parametric equations:
x= (vo*cosθ)t and y=h+(vo*sinθ)t-16t^2

The center field fence in a ballpark is 10ft high and 400 ft away from home plate. The ball is hit 3 feet above the ground. It leaves the bat at an angle of θ degrees with the horizontal speed of 100 miles per hour.

A) write a set of parametric equations for the path of the ball.
B) graph the path of the ball when θ = 15 Is the hit a home run?
C) find the minimum angle at which the ball must leave the bat in order for the hit to be a home run.
part (a)

start by converting 100 mph into ft/s to get $v_0$ in correct units

... sub in your known values

$x = v_0 \cos{\theta} \cdot t$

$y = 3 + v_0 \sin{\theta} \cdot t - 16t^2$

(b) do what it says ... graph the parametric equations in your calculator. since the fence is 400 ft away in the x-direction, solve the equation for t

$400 = v_0 \sin(15) \cdot t$

then use that value of t to find the y-position ... if it's greater than 10 ft, homerun.

(c) here's where you can use your graphing calculator to play with the angle to ATQ.