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Free-fall physics problem

  • Thread starter pjr65stang
  • Start date
  • #1

Homework Statement


A load of bricks is lifted by a crane at a steady velocity of 5.0 m/s when one brick falls off 6.0 m above the ground. (a) Sketch the position of the brick y(t) versus time, from the moment it leaves the pallet until it hits the ground. (b) What is the greatest height the brick reaches above the ground? (c) How long does it take to reach the ground? (d) What is its speed just before it hits the ground?


Homework Equations





The Attempt at a Solution


I'm not sure where to even begin. The answers are in the back of the book, and the graph for part A is completely different than I thought. A time interval isn't given. I'm just really unsure of what to do here.
 

Answers and Replies

  • #2
Delphi51
Homework Helper
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10


Welcome to PF!
We use formulas to describe the motion of a moving object.
When there is no acceleration, the formula is just d = v*t, where d is the distance, v the constant speed and t the time.
In this problem, there is the acceleration of gravity so the distance formula is more complicated: d = di + Vi*t + ½*a*t²
If you put in the initial distance di = 6, the initial speed for Vi and the acceleration of gravity -9.81 for "a", you can use the formula to find the height d at any given time. Do it for every half second from 0 to 3 or 4 seconds and you'll have enough points to graph the height vs time and answer the other questions.
 

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