Question

Henrietta is going off to her physics class, jogging down the sidewalk at a speed of 3.95 m/s . Her husband Bruce suddenly realizes that she left in such a hurry that she forgot her lunch of bagels, so he runs to the window of their apartment, which is a height 39.9 m above the street level and directly above the sidewalk, to throw them to her. Bruce throws them horizontally at a time 6.50 s after Henrietta has passed below the window, and she catches them on the run. You can ignore air resistance.
Part A

With what initial speed must Bruce throw the bagels so Henrietta can catch them just before they hit the ground?

Answer 1

Answer:

initial speed  = 12.96 m/s

Explanation:

Given data:

speed 3.95 m/s

height = 39.9 m

we know that time to reached the bottom is

$H =\frac{1}{2} gt^2$

$t = \sqrt{\frac{2H}{g}}$

$= \sqrt{\frac{2\times 39.9}{9.8}}$

t = 2.855 sec

total time taken = 2.85 + 6.50 = 9.35 s

total distance at horizontal $d = 3.95\times 9.35 = 36.95 m$

$speed = \frac{d}{t} = \frac{36.95}{2.85} = 12.96 m/s$