Introductory physics: Time for a ball thrown vertically to reach maximum height

AI Thread Summary
The discussion revolves around a physics problem regarding the time it takes for a ball thrown vertically to reach maximum height. A participant calculates the maximum height using the freefall equation and arrives at a distance of 11.4 meters. However, the main focus of the problem is to determine the time in seconds, not the height in meters. There is confusion regarding the interchange of variables "x" and "d," as well as the clarity of the images shared in the forum. The conversation emphasizes the need to address the time calculation rather than the height achieved.
danielsmith123123
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Homework Statement
A 3 kg ball is thrown vertically into the air with an initial velocity of 15 m/s. What is the time it takes for the ball to reach its maximum height?
Relevant Equations
Vf =vi +at
Vf^2 = Vi^2 +2ax
x = Vf t - (1/2)(a)(t^2)
x = Vi t + (1/2)(a)(t^2)
Is the answer key wrong? I keep getting the same answer and it is verified with the freefall equation distance=1/2 (g)(t^2)
IMG_5721[1120].PNG
 
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You should write the full text of the problem, not an abstract of it. Where did the value of d comes from?
 
Ok thank you, i edited the forum. I guess you can't open pictures on this website, but i calculated d with Vf^2=Vi^2 +(2)(a)(d)
0^2 = 15^2 + (2)(-9.8)d
d = 11.4m
(I realize i probably shouldn't use "x" and "d" interchangibly)
 
You found the maximum height. The problem is asking you to find the time it takes to reach that maximum height. Your answer should be a number in seconds, not meters.
 
danielsmith123123 said:
Ok thank you, i edited the forum. I guess you can't open pictures on this website, but i calculated d with Vf^2=Vi^2 +(2)(a)(d)
0^2 = 15^2 + (2)(-9.8)d
d = 11.4m
(I realize i probably shouldn't use "x" and "d" interchangibly)
You don't need the height but you got it OK. What is your problem? I cannot read the image you posted. It is not clear enough.
 
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