Calculating Height & Velocity of a Tennis Ball Hit at an Angle

[dopey9]

a tennis ball is hit from a height h above the ground with a speed V and at an angle alpha to the horizontal. it hits a wall at a horizontal distance d away . Air resistance is negligible

can anyone find expressions for the height and velocity of the bal when it his the wall for me to compare?

thankz

 

[dt19]

try resolving the velocity into horizontal and vertical components. then see what you can do with the suvat equations.

 

[DLinkage]

This is the case of simplified projectile motion, let me give you a crash course somewhat quickly.

If we assume gravity is the only acting force on the ball then the horizontal component of its velocity is a constant since the gravitational force is assumed to be entriely vertical. (downwards of course)

Thus Vx = Vo*cos(alpha)

Where Vo is the initial velocity and alpha is the launch angle measured TOWARDS the upward vertical FROM the horizontal in the direction of motion.

Vx is the x component of velocity

By applying some basic kinematics we find Vy = Voy*sin(alpha) - g*t

From the pythagorean theorem V = sqrt(Vx^2+Vy^2)

now the goal for you is to find the time at which the ball has traveled a distance d.

I'll give you a hint:

set D = Vo*cos(alpha)*t and solve for t.

Notice that the displacement kinematic equations given the assumptions are:

X = Vo*cos(alpha)*t
Y = Vo*sin(alpha)*t - 1/2*g*t^2

Assume you start at (x,y) = (0,0) and you will end at the point (D,h)