Physics Study of Motion

Physics: Study of Motion

 

• Newton's first law referred to as the law of inertia.
• According to Newton, an object will only accelerate if there is a net or unbalanced force acting upon it.
• Newton's second law states that the acceleration of an object is dependent upon two variables – the net force acting upon the object and the mass of the object. A force that will work against motion in every situation is friction
• A rocket is traveling from Earth to Mars at 10,000 m/sec. If no outside force is applied to it, its speed over the course of the trip stay constant
• When a car suddenly stops, the objects in the back seat are thrown forward. This is due to inertia
• If the object is NOT moving, the acceleration coming from to cause the force to increase as the mass increases is gravitational force
• Newton's Laws which describes the relationship between the mass and force is Law of force and acceleration
• The tendency of an object to resist a change in motion is called inertia.
• If an object has mass, it also has inertia.
• An object with more mass has more inertia
• My whole body doesn't sink into the sand because the sand is pushing back up against my foot. Newton's Third Law explains this situation.
• Recoil of gun and motion of rocket are example of Newton's third law
• When two particles collide, each other experience the same force, the same impulse, and same momentum change.
• The impulse of a force can be zero, even if the force is not zero.
• Newton's law of universal gravitation states that a particle attracts every other particle in the universe.
• With a force which is directly proportional to the product of their masses
• And this force is inversely proportional to the square of the distance between their centers.
• value of Universal gravitational constant in our world is G=6.67×10−11??2/??2
• The direction of the force of gravity is in a straight line between two objects. It is always attractive
• Gravitational force that sun exerts on moon is twice more than that of earth exert on it.
• Mass is both a property of a physical body and a measure of its resistance to acceleration when a net force is applied
• SI unit of mass is Kilogram(kg).
• Mass of the body does not change.
• weight of an object is related to the amount of force acting on the object, either due to gravity or to a reaction force that holds it in place
• Mass is not the same as weight.
• SI unit of Weight is Newton (N)
• The acceleration which is gained by an object because of gravitational force is called its acceleration due to gravity.
• SI unit of acceleration due to gravity is m/?2
• Momentum is the product of the mass and velocity of an object.
• SI units, it is measured in kilogram meters per second (kg⋅m/s)
• According to law of conservation of momentum, momentum before collision is always equal to momentum after collision.
• The force applied on a surface in a direction perpendicular or normal to the surface is called thrust.
• Force, and thus thrust, is measured in the International System of Units (SI) as the newton (symbol: N).
• Pressure (symbol: p or P) is the force applied perpendicular to the surface of an object per unit area over which that force is distributed.
• Unit of pressure is Pascal.
• Momentum is related to Newton's 1st law.
• A person in car slides to the right when going through a very sharp left turn on the highway due to inertia.
• The force of gravity exists between any two objects that have mass.
• If the horse reared up on 2 legs it will exert twice the pressure it did before
• The deeper you go under the sea, the greater the pressure of the water pushing down on you.
• If we pull our diaphragm down, air goes into our lungs because the volume increases and so pressure decreases.
• If we double the mass of one object, but don't change anything else, the gravitational force between two objects doubles.
• As distance between two objects increase the pull of gravity decreases.
• The measure of the pull of gravity on an object is called weight. If lift is going up with acceleration, the apparent weight of a body is more than the true weight.
• An object kept in a lift which falls freely, weighs zero.
• Pressure change occurring anywhere in a confined incompressible fluid is transmitted throughout the fluid such that the same change occurs everywhere.
• Hydraulic lift works under the principle of Pascal's Law.
• Jupiter is the planet with largest value of gravitational force.
• A body will have maximum weight in Jupiter (in the case of planets).
• Weight of a body at poles will be higher than that at equator.
• This is because equator will have maximum effect of centripetal force.
• Centripetal force at poles are zero.
• Wall of a dam is made broader at bottom to withstand the pressure that increase with depth.
• Mano meter is used to measure liquid pressure.
• A liquid exerts pressure in all directions.
• If the area over which force acts is decreased, then the pressure is increased.
• The acceleration due to gravity on the surface of the Moon is about 1.625 m/s2, about 16.6% that on Earth's surface.