Mechanical Engineering
• 0

# Tackles...

## Question

I've always being fascinated by tackles because they seem "magical" to me. In the picture below the force needed to lift the weight is reduced 4 times and adding up 1 pulley it would be reduced 8 times and so on......So my question is: what's the limit? Using a 100 pulleys tackle could i lift up my car with my little finger?  Thanks in advance

## Recommended Posts

• 0

Friction eventually imposes a limit. If there were no friction, you could just add pulleys ad infinitum, but in reality, each new pulley adds friction to the system. Eventually you would get to a point of diminishing returns.

DrD

##### Share on other sites
• 0

Thank you very much Professor!

##### Share on other sites
• 0

Also, adding more pulley means that the vertical movement reduced for each additional pulley.

using 1 pulley, F = W, you move F 1 m, you get W lifted for 1 m.

using 2 pulley, F = W/2, you move F 1 m, you get W lifted for only 0.5 m.

using 3 pulley, F = W/3, you move F 1 m, you get W lifted for only 0.333 m.

But mostly, what DrD said.... friction

##### Share on other sites
• 0

Is there anybody who can post the free body diagram of the above winch? Thanks in advance

## Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

×   Pasted as rich text.   Paste as plain text instead

Only 75 emoji are allowed.

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×