A ball is droppred from a roof and takes 3.0 s to reach the ground. Calculate the elevation of the roof above the ground in meters. (Neglect air resistance)
2007-09-30 16:17:39 · 5 answers · asked by Ice Cube 1 in Science & Mathematics ➔ Physics
where does the 9.8 m/s² come from i dont get it
2007-09-30 16:30:56 · update #1
d = vot + 1/2 at^2
d = 0 x 3.0s + 1/2 x 9.8 m/s^2 x (3.0s)^2 = (4.9 x 9) m = 44.1 m
since your 3.0 s only has two sig figs, the answer should be reported as 44 m
2007-09-30 16:23:10 · answer #1 · answered by Dr W 7 · 2⤊ 0⤋
Any object is pulled down by earth with an acceleration of g = 9.8 m/s^2 toward the ground.
That is to say the velocity increases by 9.8m/s in every second.
Hence the ball's speed increases to 3 x 9.8 = 29. 4 m/s.
This is calculated using the formula v = u + at
v = 0 + 9.8 x 3 = 29.4 using u =0 initial velocity is zero.
The distance traveled is found using average velocity x time.
The average velocity is [0 + 29.4] / 2 = 14.7 m/s.
Distance traveled is 14.7 x 3 = 44.1 m.
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2007-10-01 04:49:17 · answer #2 · answered by Pearlsawme 7 · 0⤊ 0⤋
s = (1/2) at² and you know a is 9.8 m/s². It's just plug 'n chug.
s = (1/2)*9.8*3² = 44.1 meters
Doug
EDIT: Freak needs to take a physics class or two.
2007-09-30 23:21:36 · answer #3 · answered by doug_donaghue 7 · 1⤊ 0⤋
g= 9.8 m/s^2 (gravity)
Ilusion
2007-10-01 05:12:13 · answer #4 · answered by Ilusion 4 · 0⤊ 0⤋
we need to know the volume and mass of the ball, coz they r factor tht influence the drop speed, even tho idk how to calculate it but i know tht we cant fidn an answer from the info u had given
2007-09-30 23:21:30 · answer #5 · answered by Freak 2 · 0⤊ 2⤋