 Collisions are really bad. I don't like collisions. But what can I do? It's a vital topic of physics, collision and momentum. Let's talk about types of collision, elastic collision and inelastic collision. Any collisions in which the collided objects get separated after the collision is known as an elastic collision. Remember, in case of elastic collision, kinetic energy gets conserved. An inelastic collision is such a type of collision that takes place between two objects in which some energy is lost. In the case of an elastic collision, momentum is conserved. But the kinetic energy is not conserved. Most of the collisions in daily life are inelastic in nature. What is momentum? Momentum is a property of objects with mass and velocity. It is a vector quantity with the same direction as the velocity of the object. The equation for momentum is mass times velocity. P is equal to mv. If mass is measured in kilogram and velocity in meter per second, so the unit of momentum will be kilogram meter per second or Newton second. According to law of conservation of momentum, momentum before collision is equal to momentum after collision. So momentum is conserved. Let's relate kinetic energy with momentum. We know that kinetic energy is half mv squared and momentum is mass time velocity. So if we want to take the velocity as a subject formula, so velocity equals to p over m. If we replace the equation number two, value of v in equation number one, so the equation is something like this. If we solve it further, we will get kinetic energy is equal to momentum squared divided by double of mass. Finally, let's talk about what is impulse. Impulse is simply the change in momentum. Impulse is a vector quantity with the same direction as the force and it is measured in Newton second. We can rearrange the impulse formula with the help of Newton second law of motion, which is f is equal to ma. So the quantity f delta t is the impulse of the force. So it can be seen that impulse is same as change in momentum.