what is newtons second law in physics
what is newtons second law
Newton's second law:
F = m a, where F is the net force acting on the body with mass m, and a is the acceleration of the body.
Attn: F is the resultant force, and both F and a are parallel vectors. Newton's second law can be applied in any direction.
Newton's Second Law states that the net force applied to an object is jointly proportional to the mass of the object and the object's acceleration.
Most teacher's simply expect their students to learn the formula "F = ma" for Newton's Second Law.
I would only add that I always tell my students that newton explained his second law in terms of acceleration. He said that accelerations are caused by net forces acting on objects. Accelerations occur when objects speed up, slow down, change direction or some combination of these. In many problems, you are given information about the acceleration, and you are then asked to find the net force that caused the acceleration using F(net) = ma. Good Luck.
Newton's 2nd Law is the source for all the figuring in physics. It states that any acceleration of an object (acceleration is a vector with both magnitude and direction) will be in the direction of the net force (a vector as well), and will be directly proportional to the net force, and inversely proportional to the object's mass (inertia).
In equation speak, a = Fnet/m (where both a and F should be bold as they are vectors).
It is customary to multiply both sides by m, and switch sides to get:
F = ma. The units are Kg m / (sxs). 1 Kg m / (sxs) = 1 Newton.
Newton's first and third laws are more qualitative. Newton's second law is quantitative and allows for an accounting of acceleration, force, and mass.
According to to Newton's Second Law, all the below answers are true! If an object...say a car... is sitting still and pushed with enough force to overcome static friction(friction resulting from the resting mass on a surface), then the object can accelerate from rest.
Once the car is already in motion, but not going any faster (constant velocity), there is equilibrium between the applied force and the frictional force. The car is coasting in cruise control, so there isn't any "net force". Mathematically...Net force = Force applied - Force of friction. And, if they're equal, you'd get zero.
So, what to do if you want to speed up in the car?....Press the accelerator using force. The added force of the engine will surpass the equilibrium the car will go faster. A more accurate example would be a scooter. A net force that overcomes friction and surpasses it will allow the object to accelerate. Zoom, zoom!