Physics chapter 4

Force

Force

a push or pull

Gravitational Force

The force of attraction between 2 or more masses at some distance (strength: weak scale: large) ex. Earth and sun

Electromagnetic force:

Force of attraction/repulsion between opposite/like charges/poles at some distance. (Strength: 1x10 x's stronger than Fg Scale: small) ex. Atoms {+ nucleus, - electrons)

Strong nuclear force:

Force that binds the nucleus (Strength: 100x's than Fe&m scale: tiny) ex. Nucleus (protons and neutrons)

Weak nuclear force:

Force that governs radioactive decay

radioactive decay:

When an unstable nucleus emits particles or light to gain stability (Strength: 1x10 weaker than Fsn [most of the time] Scale: tiny) ex. Beta decay

Grand unified theory:

The search for one force

Grand unified theory proof

1. Maxwell unified electricity and magnetism

2. Gravitational lensing: curved space which is believed to cause gravity appears to bend light

NEWTON'S LAWS OF MOTION

1.)law of inertia: an object at rest will stay at rest and an object in motion in a straight line will stay in motion in a straight line unless acted on by an outside force. 2.)law of impulse: the sum of the forces acting on an object equals its mass times its acceleration 3.) conservation of momentum: every action has an equal or opposite reaction

inertia

an object's resistance to changes in motion

mass

measure of inertia

Left side of law of impulse:

what we know about how forces work

Right side of law of impulse:

what we see

weight:

the force of gravity at or near the earth's surface

normal force:

a reaction force due to contact with a surface

Friction:

force that opposes motion

coefficient of friction:

an experimentally derived constant that explains the interaction between 2 surfaces 2 types of coefficient of friction static, kinetic

• Static is always greater than kinetic.

Tension:

pull of a rope

Spring force:

recoil of a spring