# Dynamics trajectory motion help

• UCF_Martin

## Homework Statement

"In a movie scene involving a car chase, a car goes over the top of ramp A and lands a B below. Determine the speed of the car at A if the car is to cover distance d=180ft for $\alpha$ =15° and $\beta$ = 30°. Neglect aerodynamic effects.

## Homework Equations

Word.doc is the problem picture.

## The Attempt at a Solution

I have calculated the distance the car moves the in X, and falls in the Y. But other than that I am rather lost mathematically.

The hint for the problem states: "The required initial speed can be found from the intersection of the parabolic trajectory and the straight line whose slope in determined by tanβ"

Only problem is I have no idea as to what line tanβ is the slope of.

#### Attachments

• Doc1.docx
170.6 KB · Views: 309
Hi UCF_Martin, [Broken]

As the car becomes airborne at point A, two things happen: (i) it continues to travel horizontally with the same horizontal component of speed as it had at point A, and (ii) its vertical motion is controlled by gravity.

You should be able to quote in your sleep a set of equations describing motion under a constant acceleration (g = 32.2 ft/sec).

Last edited by a moderator: