My Grade 10 textbook states
When the effort arm is longer than the load arm, the mechanical advantage and Velocity Ratio of the Class 1 lever are greater than one.
When the effort arm is longer than the load arm, the mechanical advantage and Velocity Ratio of the Class 1 liver are greater than one
Now, I have understood that since
M.A. = Effort Arm/ Load Arm
Therefore M.A. is greater than one.
But I am unable to reach this conclusion in the case of Velocity Ratio. I am unable to understand how did my book reach this conclusion. Can someone please explain this to me that how to deduce Velocity Ratio of a lever in cases like this?
Best Answer
Well, simply put, the Velocity Ratio is defined as such:
VR = Velocity of effort / Velocity of Load
Since the effort arm is longer, the distance it travels is also greater than that of the load arm. They both move (travel) for the same amount of time. This means that the effort is moving with a greater velocity (speed = distance/time)
Therefore the VR is greater than one.
A qualitative way to think of why both of them must be greater than one is that you are applying less effort than normal to move a load, but the 'cost' is that you now have to apply this effort over a larger distance. I don't know if you've studied conservation of energy yet, but if both VR and MA were not greater than one it would violate one of Physics's favourite laws!