I have a problem I am stuck on?
According to Guinness the tallest man who ever lived was Robert. He was last measured in 1940 to be 2.72 (8 ft 11 in). Determine the speed in which a quarter would have reached before contact with the ground if dropped from rest from the top of his head.
Please help me answer this. I am confused
回答 (3)
Initial velocity = u = 0
Final velocity = v
Distance = 2.72 m
gravitational acceleration = 9.8 m/s²
From one of the laws of motion we get
v²=u²+2as = 0 + 2(9.8)2.72 = 53.312
v = 7.3 m/s
t = √2h / g
v = at
plug the "t" equation into "v = at"
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v = a√(2h / g)
v^2 = a^2/g * 2h
v^2 = 2ah
v = √(2ah)
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We can do this in feet or meters, meters first:
m = 2.72
g = 9.81
v = √(2*9.81*2.72) = 7.3 m/s
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Feet
v = √(2 * 8.92 * 32.2) = 23.4 ft/s
Let s = the distance = 2.72 m
Let a = the acceleration due to gravity = 9.81 m/s²
Let v = the speed of the quarter
The equation for this can be derived from the equations for distance and speed
s = (1/2)(a)t²
v = (a)t
Substitute v/a for t into the first equation:
s = (1/2)(a)(v/a)²
s = (1/2)v²/a
2(a)s = v²
v = √{2(a)s}
Now you should be able to calculate the speed.
收錄日期: 2021-04-21 00:14:01
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