# How to Calculate Force Ratio for lifting a vehicle using a screw jack

## What is the required force ratio for the vulcanizer to raise the vehicle with the screw jack?

If the efficiency of the jack is 75/pie %, what force ratio has the vulcanizer inputs to get the job done conveniently?

## Answer:

In order to calculate the required force ratio for the vulcanizer to raise the vehicle with the screw jack, we first need to determine the required torque for the screw jack to lift the load. The torque required is equal to the force applied to the end of the arm of the screw jack multiplied by the length of the arm.

If the pitch of the screw is 0.45 cm, and the arm is 60 cm long, the required force to lift a load with the screw jack can be calculated using the following formula:

**Force = Torque / Arm length**

Plugging in the values we know, we get:

**Force = (Torque / 60 cm) / (0.45 cm/rev)**

Where "rev" refers to one revolution of the screw.

To raise the load with an efficiency of 75/pi%, we need to input a force that is sufficient to overcome the load and the friction in the system.

The required input force can be calculated using the following formula:

**Input Force = (Required Force / Efficiency) * (100 / pi)**

Plugging in the values we know, we get:

**Input Force = (Required Force / (75/pi)) * (100 / pi)**

The input force ratio is the ratio of the input force to the required force. To get the required input force ratio, we can divide the input force by the required force:

**Input Force Ratio = Input Force / Required Force**

I hope this helps! Let me know if you have any other questions.