Solving a Physics Problem: How Far Will the Ball Land?

[luke34]

Ok here's the problem:
A batter hits a ball which leaves the bat 1 meter above the ground at an angle of 65 degrees with an initial velocity of 30 m/s. How far from home plate will the ball land if not caught and ignoring any air resistence?

So I tried solving for how much of the velocity is is the x and y components.
X= Vcos65
Y= Vsin65
which gave me x=12.68 and y=27.19

Then using the equation X=X(initial) + V(initial x)T + .5A(x)T^2
I plugged in my numbers to get 0=1+12.68t+.5(9.8)T^2.

This is where I'm stuck. Am I on the right track or what? Help please. Thanks.

 

[Dorothy Weglend]

That equation is for the vertical motion only, so it won't give you the range, which is what this problem is asking for. It actually doesn't make any sense to use the x component in that way, in that equation.

But this equation would be useful in finding the time it would take to land on the ground after being hit.

Then perhaps you could figure out how far it would travel in the horizontal direction in that time, and that would give you the range.

Dorothy

 

[luke34]

So what exactely am I suppose to do if I shouldn't use the x componet to solve for time?

 

[Dorothy Weglend]

Why use the horizontal component of motion in an equation which describes the vertical motion of the object? Use the Y component.

 

[luke34]

Oh I see. Seems so obvious now. Thanks