How the jack exerts a force?
A vehicle jack exerts at least two forces, one up on the vehicle equal to the vehicle weight and one down on the ground equal to the vehicle weight plus the jack weight. Of course gravity exerts a force equal to the vehicle weight so that the net force on the jack is zero. You increase the force up on the vehicle and down on the ground with a lever or screw that makes the jack longer.
Or, besides lever or screw, one can use hydraulic force (see Pascal's principle)
The jack exerts a force by utilizing a principle of physics known as hydraulic pressure. A hydraulic jack is a device that is commonly used to lift heavy loads. It consists of a small cylinder with a piston inside it, a larger cylinder with a movable piston, and a fluid (usually oil) that fills both cylinders.
To understand how the jack exerts a force, we need to consider Pascal's law, which states that when pressure is applied to a fluid in a confined space, the pressure is transmitted equally in all directions. Here is how a jack utilizes this principle to exert force:
1. The jack is placed under an object that needs to be lifted, with the small cylinder (containing the small piston) at the bottom and the large cylinder (containing the large piston) at the top.
2. A force is applied to the small piston by manually pumping a handle connected to it, which increases the pressure of the fluid in the small cylinder.
3. According to Pascal's law, this increase in pressure is transmitted equally in all directions, including to the fluid in the larger cylinder.
4. The increased pressure in the larger cylinder exerts a greater force on the larger piston, which pushes against the object being lifted.
5. By continuing to pump the handle and increase the pressure in the small cylinder, the force exerted by the larger piston continues to increase, allowing the jack to lift heavier objects.
In summary, a jack exerts a force by using hydraulic pressure to multiply the force exerted on the small piston and transmit it to the larger piston, which then pushes against the load that needs to be lifted.