Solve a Golf Ball Physics Problem: Calculate Velocity After 2.84s

[yankee]

A golf ball is released from rest from teh top of a very tall building. Choose a coordinate system whose origin is at the starting point of the ball, and whose y-axis points vertically upward. The acceleration of gravity is 9.8 m/s^2. Neglecting air resistance , calculate the velocity of the ball after 2.84s. ANswer in units of m/s.
---ok basically i have tried this question about 3 times and each time i have gotten it wrong. The first two answers made absolutely no sense and the third answer i got was 185.3543
this is how i did it:
Vf= 9.8m/s^2(2.84s)^s
= 60.27392
then i did
60.27392^2= 2(9.8 m/s^2x)
i got 185.3543
----
please reply asap i have no clue how to solve this- i thought i was correct but apparently not. what formulas should i use? How would i go about to getting the answer? THANKS SO MUCH

 

[BunDa4Th]

V = V_o + GT
DeltaY = V_oT + 1/2GT^2
DeltaY = Y_f - Y_i

V_o = 0
Y_i = 0

G = -9.8

I hope that help.

It seem you made gravity 9.8 when it should be -9.8 since gravity is going down so it would be negative.

 

[kyle8921]

Hi there,

It looks like you're on the right track with using the formula for velocity (Vf = Vi + at). However, there are a few things to keep in mind when solving this problem:

1. Make sure your units are consistent throughout the calculation. The acceleration of gravity is given in m/s^2, so your final answer should also be in m/s.

2. You need to start with the initial velocity (Vi) of the golf ball. In this case, the ball is released from rest, so the initial velocity is 0 m/s.

3. The acceleration (a) in this problem is the acceleration due to gravity, which is always pointing downward. So, it should be -9.8 m/s^2, since the y-axis is pointing upward.

With these adjustments, the equation becomes Vf = 0 m/s + (-9.8 m/s^2)(2.84 s) = -27.872 m/s. Note that the negative sign indicates that the velocity is pointing downward.

I hope this helps! Keep practicing and don't get discouraged - physics can be challenging but with practice, you'll get the hang of it. Good luck!