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Mechanics Newton's 2nd law question

  • Thread starter pianogirl
  • Start date
  • #1
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Homework Statement


A load of 200kg is lifted through 50m by a vertical cable. The load accelerates uniformly from rest for 20 seconds, travels at constant speed for 10 seconds then decelerates to rest in a further 10 seconds. Find the maximum speed attained and the tension in the cable at each stage.



Homework Equations


F=ma and maybe some SUVAT ones?



The Attempt at a Solution


I started using F=ma so that for the first stage I got T=200a+1960 but soon after that I got a bit confused.

Help would be really appreciated because I'm stuck!
Thanks!
 

Answers and Replies

  • #2
tiny-tim
Science Advisor
Homework Helper
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Hi pianogirl! :smile:

Forget the tension … you need to find the acceleration before you can find the tension. :wink:

Write out the standard constant acceleration equations for the three stages of motion, plus the equation that says the three distances add to 50m.

What do you get? :smile:
 

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