Newton's Three Laws of Motion Newton's First Law: Law of Inertia An object at rest tends to stay at rest, and an object in motion tends to stay in motion with t...
An object at rest tends to stay at rest, and an object in motion tends to stay in motion with the same speed and direction, unless acted upon by an unbalanced force. This law defines the concept of inertia.
The net force F acting on an object is equal to the product of its mass m and acceleration a. This law relates force, mass, and acceleration, and forms the basis for understanding the motion of objects.
Problem: A 2 kg object experiences a net force of 10 N. Calculate its acceleration.
Solution:
For every action force, there is an equal and opposite reaction force. Forces always occur in pairs, and the two forces are equal in strength but opposite in direction.
The linear momentum p of an object is the product of its mass m and velocity v: p = mv
The impulse J acting on an object is equal to the change in momentum Īp. In a closed system, the total momentum is conserved before and after a collision or explosion.
In an elastic collision, kinetic energy is conserved, and momentum is conserved in both magnitude and direction. In an inelastic collision, kinetic energy is not conserved, and some energy is lost as heat or sound.
Problem: A 0.5 kg object moving at 10 m/s collides elastically with a 1 kg object initially at rest. Calculate the final velocities of both objects.
Solution:
This topic forms the foundation for understanding the motion of objects and the principles of momentum and energy conservation, which have numerous applications in physics and engineering.