if 20n of effort has made for 25m that has load moved 3m in hight find the velocity ratio of the machine

To find the velocity ratio of a machine, you need to divide the distance moved by the effort (input distance) by the distance moved by the load (output distance).

In this case:
Input distance (effort) = 20n
Output distance (load) = 3m

Velocity Ratio = (Input distance / Output distance)

Velocity Ratio = (20n / 3m)

However, since we need to find the ratio in terms of n/m, we need to convert the units:

1n = 1m (since we have no other conversion factor given)
20n = 20m

Velocity Ratio = (20m / 3m)

Now, we can simplify the ratio:
Velocity Ratio = 20 / 3

Therefore, the velocity ratio of the machine is 20/3.