# General physics urgen help

The ball takes off at 30deg and lads 40 ft from there.
[Don't solve/calculate the problem, just set up axes, and make a list of what you know or don't: delta-x, delta-y, horizontal velocity, initial vertical velocity, v sub-y, a sub-y, and t.]

is this correct?:
delta-x = 40 ft
delta-y = 0
horizontal velocity = unknown
initial vertical velocity = ??? [i dunno!]
v sub-y = ??? [i dunno!]
a sub-y = 9.8 [is it positive or negative gravity?]

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tiny-tim
Homework Helper
Welcome to PF!

The ball takes off at 30deg and lads 40 ft from there.

initial vertical velocity = ??? [i dunno!]
v sub-y = ??? [i dunno!]
Hi lifeisamazing! Welcome to PF! Let's see: do you know delta-y … does the problem specifically say that the ball starts on the ground?

(A ball usually starts by being thrown from someone's hand, several feet higher than it lands!)

v sub-y is the initial vertical velocity, isn't it?

Do you know any relationship between the horizontal velocity and the initial vertical velocity?
a sub-y = 9.8 [is it positive or negative gravity?]
Careful! The distance are in feet, so the figure for gravity must be … ? As for positive or negative … which direction is it acting in?