91Ó°ÊÓ

Weight is the force with which gravity pulls an object towards the Earth. It is a type of force that acts downward and is always directed towards the center of the planet. The weight of an object can be calculated using the formula:

• \( w = m imes g \)

Here, \( m \) is the mass of the object, and \( g \) is the acceleration due to gravity, which is approximately \( 9.8 \, \text{m/s}^2 \) on the surface of Earth.
This means that weight depends on both the mass of the object and the gravitational pull of the Earth. Since gravitational acceleration is constant on Earth’s surface, an object's weight will be directly proportional to its mass. Increasing the mass will increase the weight, and vice versa.
Understanding weight is crucial as it allows us to determine how much force is needed to lift or hold an object.

Equilibrium refers to a state where all forces acting on an object are balanced. When an object is in equilibrium, it does not accelerate or change its state of motion. There are two main types of equilibrium—static and dynamic:

• Static Equilibrium: This occurs when an object is at rest, and all forces acting upon it are equal and opposite, which means it stays in one place without moving.
• Dynamic Equilibrium: This happens when an object is moving at a constant velocity, and again, all forces acting on it are balanced.

In static equilibrium, the net force is zero, which means the sum of all forces, including the normal force and weight if considering vertical forces, should equal zero.
It is essential to recognize when an object is in equilibrium as it helps in figuring out the forces at play, especially when solving physics problems related to forces and motion.

Net force is the total force acting on an object, found by combining all individual forces. It determines whether the object will accelerate, remain at rest, or move with constant velocity. The net force formula is:

• Net force = Sum of all forces acting on the object

In scenarios where objects are in equilibrium, like our original problem, the net force is zero. This is because the forces acting on the object are balanced.
For instance, when you have both weight and normal force acting in opposite directions and are equal in magnitude, they cancel each other out, resulting in a net force of zero.
Understanding how to calculate and interpret net force allows us to predict the motion of objects and is a fundamental concept in physics.

Gravity is the universal force of attraction that exists between all masses. On Earth, gravity gives weight to physical objects and causes the downward force on them. The force of gravity on an object near the surface of the Earth can be calculated with:

• \( F = m imes g \)

Where \( F \) is the gravitational force (or weight), \( m \) is the mass, and \( g \) is the gravitational acceleration \( (9.8 \, \text{m/s}^2) \).
Gravity is why objects fall to the ground when dropped and why we have weight. It also affects the movement of planets and moons in their orbits.
To fully understand interactions on or near Earth, accounting for gravity is vital, as it significantly influences both the equilibrium and net force on an object.