# How to calculte Kinetic Energy of Scissor Lift system

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1. Apr 29, 2015

### Ycean

Hi, here i need to calculate the tilt angle of the scissor lift. I had done some reviews for designing a scissor lifter, some source state that, tip-over will happen only when the kinetic energy of the system is less than the Potential energy after impact.
Hence, i was trying to use this relation to find out the range of the best angle. But, i don't know how to calculate the Kinetic Energy of the whole system. Can anyone give me some idea to solve it?Thankyou in advance!!

2. Apr 29, 2015

### Staff: Mentor

Which source? That sounds strange.

Do you have a sketch, including where you expect an impact?

3. Apr 29, 2015

### Ycean

If not mistaken it is from a journal of the research paper, but inside that paper din't describe much about why the kinetic energy lesser than potential energy of the system will cause the tip-over to happen. And i just only jot down the factors that might leading the tip over to happen, during i did my literature review.
Actually what i concern now is how to calculate the tilt-angle. Because i need it for my scissor structure design. Can anyone kindly give me some advises. ><"".Thanks!!

4. Apr 30, 2015

### Staff: Mentor

Have you got a link to a textbook problem dealing with what you are talking about?

5. Apr 30, 2015

### Ycean

Here was the paper i got. In the Chapter 2,the author did mention about the potential energy after impact greater than Kinetic energy will lead the tip-over to happen.

6. Apr 30, 2015

### Ycean

I did try to look at all my mechanical text book for dynamic or static analysis. And what i found is, scissor lifter having only one degree of freedom, mean this structure having only vertical motion. Therefore, i try to calculate the velocity of the lifter by differentiate the vertical displacement of the center of mass of the whole structure. After comparing both potential and kinetic energy, there was a huge differ. The kinetic energy has a much lower value than the potential energy value. It seem something is wrong.

Wondering about the statement from the research paper.

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7. May 2, 2015

### CWatters

Can you post a link to the whole paper?

When they say "KE prior to impact" I took that to mean 0.5mv^2 where v is the horizontal velocity. Not sure why you are looking at the vertical velocity.[/quote][/quote]