How does newton's law of force and acceleration relate to the movement of objects?

Answer 1

1. An object at rest will tend to remain at rest.

2. An object will remain at rest or move a straight line unless acted upon by another force.

3. Every action has an equal and opposite reaction.

Answer 2

It dosen't; any object moving in a circle is being acted on by a force towards the centre of the circle (a centripetal force). However, although there is a constant force, since it is always perpendicular to the velocity of the object it does no work. So the object can move in a circle forever without any energy being supplied to the system.

Answer 3

-- "Velocity" is defined as the description of the direction an object is moving and its speed in that direction.

If either or both of those items is changing, then the velocity is changing. Any change in velocity is defined

as "acceleration".

-- An object with no force acting on it moves in a straight line. The only way to cause it to deviate from

straight-line motion is with force. An object that's not moving in a straight line must be experiencing a

force. If it were not, then it could only move in a straight line.

Answer 4

Newton's First Law of Motion

An object at rest that has no net force applied to it will stay at rest. An object in motion that has no net force applied to it will stay in motion, traveling at the same constant velocity, including speed and direction.

Newton's Second Law of Motion

An object with a net force applied to it will accelerate proportional to the force and inversely proportional to the object's mass. The equation is f = ma, where f is the force, m is the mass, and a is the acceleration.

Newton's Third Law of Motion

An object with a net force applied to it will exert an equal and opposite force against the applied force.

Newton's Universal Law of Gravity

Two objects having mass will exert a force of gravity on each other, causing them to be attracted to each other. This force is proportional to the mass of the two objects and inversely proportional to the square of the distance between them. The equation is f = Gm1m2/r2, where f is the force, (big) G is the universal gravitation constant 6.67428 x 10-11 N (m/kg)2, not to be confused with the local gravity, which is actually f in this equation, m1 and m2 are the masses of the two objects, and r is the distance between them.

Some Examples

Take a Baseball, hold it in the air, and drop it. It falls to the ground due to the force of gravity the ball and the Earth exert on each other. There is a second force in play, the force of friction of the air imposed on the ball, which tends to counteract the falling of the ball. This air friction is very small but grows larger and larger the faster the ball gets, until it reaches a point of equilibrium with gravity. At that point, the forces on the baseball are balanced and it does not accelerate any more.

Take that same baseball, toss it up a bit, and hit it with a bat. The bat exerts a large impulse force to the ball, very quickly accelerating it. Once the baseball stabilizes, it has a parabolic trajectory up and then down, away from the bat. The horizontal velocity of the baseball is relatively constant, though slowing down due to the force of air resistance. The vertical velocity of the baseball decreases uniformly as it goes up, slows down, and then comes back down, due to the force of gravity between the baseball and the Earth. The trajectory is a parabola because the second degree integral of the force of gravity, i.e. distance, is a second order quadratic equation.

Take a rocket ship and accelerate it into space, eventually into a trajectory that is horizontal. The reaction force of the rocket thrust moves it up and then horizontally. Once in space, if all of the calculations were done correctly, the rocket will be in orbit around the Earth. Its path is circular or elliptical, caused by the force of gravity between the rocket and the Earth. In space, however, there is no air, so there is no air friction, so the rocket continues its orbit around the Earth. Had there been air, or had the rocket not gone high enough, air friction would slow it down and it would fall back to the Earth in a parabolic curve, just like the baseball.

Answer 5

Newton's Second Law is:

F = ma

In words: force is the product of mass x acceleration. You might also say that acceleration is force/mass.

Acceleration is the change of velocity divided by the time, so it always involves a change in velocity.

Answer 6

Cause of the centripetal and centrifugal forces

Answer 7

because its science