can u do this?

Question

A boy standing in a ditch throws a baseball upward toward his father. The ball leaves his hand at ground level, with an initial speed of 14.0 m/s, at an angle of theta = 61.0 degrees from the horizontal. The boy's father reaches up and catches the ball over his head, at a height of 2.0 m above the ground. The father catches the ball on its way down (as shown in the Figure). Calculate how long the ball is in the air. ( g = 9.81 m/s2)Hint: You do not have to separate the upward and downward parts of this motion. You have enough information to find the horizontal and vertical components of initial velocity. You know the vertical displacment and acceleration. Be careful with signs.

Answer 1

yes, I can do this

but what would be the point

YOU are the one that needs to learn to do this

first remember that the sin(61deg)*14.0 m/s represents the intitial velocity in the vertical direction

the vertical displacement is 2.0 meters

the equation tells us that
x=1/2 at^2 + Vot

2.0 = 1/2 (-9.81) t^2 + 14*sin(61)t
2=.5(-9.81)t^2+12.1t
2=-4.91t^2+12.1t

-4.91t^2+12.1t-2=0

pull out some quadratic formula on this quadratic and you will get two roots, one will be the time when the ball was 2 meters high on the way up (the smaller time) and the other will be the time when the ball was 2 meters high on the way down

now that you have the time that the ball was in the air

you just have to remember that 14*cos(61) will give you the horizontal initial velocity

this velocity does not experience acceleration and so the equation

x=v*t works (the distance is just the velocity times the time)

so, you know the time from the first part
you know the x velocity

you can find out how far away the father is (although looking back at the problem, I don't see that it asks for that, which is odd, because these kind of problems always ask for that)

go for it

and be sure and check my math (I did this real quick)

Answer 2

i only know the formula when you throw it straight up 90 degrees, its

s(x) = -16x^2 + initial speed (x) + distance from ground

sorry i cant help you with this one.

Answer 3

by the way this is physics not math
and also you did not say to nelect air resistanc/friction