Force and Pressure

FORCE- push or pull that affects an object; SI unit of magnitude of force (newton 'N'), & it also has a direction. Effects of FORCE:-

Change in speed- if force is applied to a moving object in the same direction, the speed of the object increase. When we apply force in the opposite direction to that of the motion of the object, the speed slows down.

Stop a moving object- a force can bring a moving object to rest.

Make a stationary object move- a force may not always cause an object to move. We need to overcome the limiting friction to move an object

Change in direction of moving body

Change in shape of the object

Types of FORCE

Non-contact forces

Contact forces

Frictional force- the force opposing the motion of the object. Opposes motion when two surface move to tend to move with respect to each other- friction

Mechanical force- the force generated by the machine. We supply energy to the machines.

Muscular force- requires action of muscles to exert force by our body.While applying muscular force, object has to be in direct/ indirect contact with it.

Magnetic force- The force acting between a magnet and a magnetic material. Unlike poles attract while like poles repel.

Gravitational force- The force of attraction between objects with mass. Doesn't need any kind of physical contact.

Electrostatic force- The force of attraction or repulsion between electric charges.

Two or more forces acting on an object is said to be balanced if the net force effect produced by all of them on the object is zero. The balanced force do not change the state of the body.

However, if the net effect produced by two or more forces on an object is not zero. The unbalanced forces change the state of the body. the object will move in the direction of the larger force. Net force= larger force- smaller force. If the two forces are acting in the same direction. The total force will be the sum of the two forces.

Pressure is force acting on a unit area. Pressure = Force/ Area. SI unit- Pascal (Blaise Pascal). Bar is another unit of pressure.

Liquid Pressure- measured by manometer. Liquid pressure is directly proportional to depth and it seeks its own level.

Atmospheric Pressure- measured by a barometer. Maximum at earth's surface and decreases with altitude.