Newton second law of motion states that- When a force acts upon a body, it imparts an acceleration proportional to the force and inversely proportional to the mass of the body and in the direction of the force.
This law can be formulated in many different ways, we'll cite here a few other formulations to help in understanding it.
The acceleration of an object of constant mass is proportional to the net force acting upon it. If an unbalanced force is acting upon an object this object accelerates. The acceleration is proportional to the net force causing it and has the direction of that force.
From the last formulation we deduce that unbalanced force means the same thing as net force. Acceleration caused by the acting force always has the direction of that force and this is obvious from the formula defining Newton's Second Law of Motion. [ F=ma]
Newton's Second Law describes the relationship between force, mass, and motion, and is an essential tool used to unravel the mysteries of the mechanical Universe.
Newton's Second Law describes the change in motion an object with mass experiences when a force is applied. This law is describe mathematically by a simple equation.
F=ma
Where F is the force applied, m is the mass of the object, and a is the acceleration experienced by the object. Acceleration is defined as a change in motion over time, and physicists lump both an increase in speed (acceleration), and a decrease in speed (deceleration) into their definition of acceleration. In this definition, a deceleration will result in a negative force. This seems a little odd, until you think of a force as either a push or a pull. If the result is negative, the force is in the opposite direction. Forces are vectors. A vector is a quantity that has both a direction and a magnitude (value). Acceleration is also a vector, but mass is not.
Newton's Second Law also means that if a constant force is applied to an object, resulting in motion, that object will accelerate. If the force is then removed, the object will maintain a constant speed unless otherwise acted upon by another force (Newton's First Law). Often, more than one force will be acting on an object at one time. It is the sum of these forces that ultimately determine the acceleration.
Multiple forces can act on an object from different directions. This affects the sum of the forces (net force). If two forces of equal magnitude are acting on an object in exactly opposite directions, the sum of the forces is zero. If two forces of equal magnitude act on an object in the same direction, the sum of the forces is double one of the forces. Mostly though, forces aren't equally opposite or equally the same. The net direction of the net force is determined by the angles between the directions of the different forces. Calculating the net force requires a little bit of trigonometry. This is simple enough in a two dimensional system, but gets more complicated in three dimensions.
It is also important to note that the mass of an object never changes no matter where it is in the Universe. Mass should not be confused with weight, which is actually the force experienced by a mass when acted on by acceleration due to gravity.
comparison with first law -The second law of motion determines the effect of net force on a body. The first law only defines the natural state of the motion of a body, when net force on the body is zero. It does not provide us with any tool to quantitatively relate force and acceleration (rate of change in velocity).
newton second law in terms of momentum-Newton's second law is all about momentum. We should Know that momentum is the product of mass (m) and velocity (v). So what does momentum depend upon? In fact it does not depend upon mass. It depends upon the force applied on the body.
Second Law of Motion in terms of momentum: The rate of change of momentum of a moving body is proportional to and in the same direction as the force acting on it ie F = d(mv)/dt, where F is the applied force, v is the velocity of the body, and m its mass. if mass remains constant, F = mdv/dt or F =ma, where a is the acceleration The direction of acceleration is the same as that of F.
As F = ma it follows that for a fixed mass, greater the force, greater the acceleration. The harder you throw a ball the greater will be its acceleration and the further it will go!
An application of newton second Law:-In a cricket match a fielder moves his arms back while trying to catch a cricket ball because if he tries to stop the fast moving ball suddenly then the speed decreases to zero in a very short time. Therefore the retardation of the ball will be very large. As a result the fielder has to apply a larger force to stop the ball. Thus, if he tries to stop a fast moving cricket ball the fielder may get hurt as the ball exerts a great pressure on the hands but if he tries to stop it gradually by moving his arms back then the velocity decreases gradually in a longer interval of time and hence retardation decreases. Thus the force exerted by ball on the hand decreases and the fielder does not get hurt.
Financial markets and global economy
Kyunki Saas Bhi Kabhi Bahu Thi 2
Pyaar Kii Ye Ek Kahaani
