posted by Tim .
A ball rolls with a speed of 6.4 m/s toward the edge of a table that is 0.7 m above the floor. The ball rolls off the table.
a. Find the magnitude of the balls velocity when it hits the floor. m/s
b. At what angle, measured from the horizontal, will the ball's velocity make with the ground? °
The ball after leaving the table
takes part in two motions: horizontal uniform motion
L = v(hor) •t,
and vertical free fall
H = gt^2/2,
t = sqroot(2H/g) = sqroot(2•0.7/9.8) = 1.43 s.
v(vert) = gt = 9.8•1.43 = 14 m/s.
tan α = v(vert)/ v(hor)=14/6.4=2.19
α = 65.4 degr
t = sqroot(2H/g) = sqroot(2•0.7/9.8) = 0.143 s.
v(vert) = gt = 9.8•0.143 = 1.4 m/s.
tan α = v(vert)/ v(hor)=1.4/6.4=0.219
α = 12.35 degr