What Is Jack's Initial Velocity When He Fell?

AI Thread Summary
Jack fell down a hill with an acceleration of 0.65 m/s², covering a distance of 11 meters in 3.7 seconds. The calculations initially attempted to find the final velocity (v2) at the bottom of the hill, but the correct focus should be on determining the initial velocity (v1) when he fell. The confusion arises from misinterpreting the units and equations used, particularly regarding the distance versus velocity. The expected answer for the initial velocity is 1.8 m/s, indicating that the calculations need to be adjusted to reflect this. Understanding the implications of a negative initial velocity is also crucial in this context.
SoConfused__
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Homework Statement


Jack went up a hill to fetch water. Jack fell down and rolled down the hill accelerating at 0.65 m/s^2 down. If he rolled 11m down the hill in 3.7s, with what velocity was he moving when he fell?


Homework Equations


a = v2 - v1/t
v2 = at + v1


The Attempt at a Solution


(0.65m/s^2)(3.7s) + 11
= 13.5 m/s.

I solved for v2, the velocity when he reached the bottom of the hill.
However the answer says 1.8m/s.
What am I doing wrong? Am I supposed to be looking for something else, not v2?
Even if I solved for v1, I would get a negative answer.

As usual, I am so confused.
 
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try this
R(t) = \frac{1}{2}at^2+v_it+R_i
v_i = \frac{R(t) - \frac{1}{2}at^2-R_i}{t}
 
That confuses me even more. What does R stand for?
 
SoConfused__ said:

Homework Statement


Jack went up a hill to fetch water. Jack fell down and rolled down the hill accelerating at 0.65 m/s^2 down. If he rolled 11m down the hill in 3.7s, with what velocity was he moving when he fell?


Homework Equations


a = v2 - v1/t
v2 = at + v1


The Attempt at a Solution


(0.65m/s^2)(3.7s) + 11
what's that 11, that's a length unit, not a speed unit.
I solved for v2, the velocity when he reached the bottom of the hill.
However the answer says 1.8m/s.
What am I doing wrong? Am I supposed to be looking for something else, not v2?
you are supposed to be looking for the initial velocity when he fell.
Even if I solved for v1, I would get a negative answer.
and what would the negative sign imply?
 
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