731 Newton's Laws

What is Newton’s first law?

Law of Inertia

What is Newton’s second law?

Law of Acceleration

What is Newton’s third law?

Law of Reaction

what does the law of inertia state?

an object at rest stays at rest and an object in motion stays in motion unless acted upon by an unbalanced force

what does the law of acceleration state

an object produced by a net force is proportinal to the magnitude of the net force and inversely proportional to the mass of the object

what does the law of reaction state

every action has an equal and opposite reaction

forces cause..

linear motion

torques cause…

angular motion

define linear motion

a force required to change the linear velocity

define angular motion

the movement of an object around a fixed center or axis; a torque is required to change the angular velocity

equilibrium

all forces (torques) acting on a body are balanced

static equilibrium

velocity is zero; body is not moving

dynamic equilibrium

velocity is not zero; body is moving but at a constant velocity

inertia

resistance to change in velocity of an object

mass

weight; is inertia

center of mass

the point about which all mass in a body is evenly distributed

center of gravity

the point about which the effects of gravity are completely balanced

mass moment of inertia

resistance to change in angular velocity

ground reaction forces

the ground pushes with an equal an opposite force back onto the object

impulse

force (torque) applied over a period of time

momentum

the quantity of movement or mass in motion

if a force is applied over a short period of time, what does this mean for momentum?

there is a small change in momentum

if a force is applied over a long period of time, what does this mean for momentum?

big change in momentum

Name Newton’s 3 Laws and and give an example for each.

1st law of inertia: kicking a soccer ball stays in motion until it hits the goal net which is the unbalanced force causing the ball to stop moving in the same direction at the constant speed

2nd law of acceleration: kicking a soccer ball; a long powerful kick has a long distance versus a small tap has a short distance

3rd law of reaction: heel striking on the ground and the ground imposing the same force back onto the heel

Define the relationship between inertia, mass, and moment of inertia

inertia is the general resistance to changes in motion, mass is the resistance to linear motion, and the moment of inertia is the resistance to angular acceleration

Define the relationship between static and dynamic equilibrium

both states of balance where the net force or net torques acting on a system are zero, resulting in no overall change

Define the relationship between impulse and momentum

the impulse applied to an object is equal to the resulting change in its momentum

Explain the relationship between kinematics and kinetics for linear and angular motion.

Kinematics: motion on the body

Kinetics: forces on the body

Newton’s 2nd law connects kinematics and kinetics. Kinematics describes the motion itself, while kinetics explains the forces and torques that cause motion- for both linear and angular movement.