# Thread: word problem: seed of a ball

1. ## word problem: seed of a ball

a ball rolls off a table with a speed of 2 ft/s. the table is 3.5 ft high.

determine the point at which the ball hits the floor and find its speed at the instant of impact.

find the angle theta between the path of the ball and the vertical line drawn through the point of impact

suose the ball rebounds from the floor at the same angle with which it hits the floor but loses 20% of its speed due to energy absorbed by the ball on impact. Where does the ball strike the floor on the second bounce?

As much help as possible on this would be greatly appreciated, I'm totally lost!

2. Originally Posted by cottekr
a ball rolls off a table with a speed of 2 ft/s. the table is 3.5 ft high.

determine the point at which the ball hits the floor and find its speed at the instant of impact.

find the angle theta between the path of the ball and the vertical line drawn through the point of impact

suose the ball rebounds from the floor at the same angle with which it hits the floor but loses 20% of its speed due to energy absorbed by the ball on impact. Where does the ball strike the floor on the second bounce?
you'll need the following kinematics equations ...

$\Delta y = v_{yo}t - \frac{1}{2}gt^2$

$v_{yf} = v_{yo} - gt$

$\Delta x = v_x t$

and the vector equations ...

$|v| = \sqrt{v_x^2 + v_y^2}$

$\theta = \arctan\left(\frac{v_y}{v_x}\right)$

note that $\theta$ in this equation is relative to the horizontal.

3. what do the variables represent?