10/22/13
Newton’s Laws
Newton’s Contributions
-Calculus
-Light is composed of rainbow colors
-Reflecting telescope
-Laws of motion
-Theory of gravitation
You tube video-What do you think Newton’s Laws are?
Newton’s 1st law (Law of Inertia)
An object at rest will stay at rest,
An object in motion will stay in motion,
Unless acted upon by an unbalanced force
What is a Force?
“a PUSH or PULL”
A Balanced Force
-Equal forces in opposite directions produce no motion.
-Unequal forces produce an unbalanced force which causes motion.
Inertia is the tendency of an object to resist change whether it is in motion of it is
motionless.
Unless acted on by an unbalanced force, the golf ball would sit on the tee forever.
Unless acted on by a force (gravity and air resistance) it would never stop.
If objects in motion tend to stay in motion, why don’t moving objects keep moving
forever.
A book sliding across the table eventually stops because of friction.
If you throw a ball in the air, it everntually falls because of gravity.
Four types of friction:
Sliding friction: ice skating
Rolling friction: bowling
Fluid friction: air/water resistance
Static friction: initial friction when moving an object
Car crashes into wall gif.
Because of inertia, objects (including you) resist changes in their motion. When the
car going 80 km/hour is stopped by a brick wall, your body keeps moving at 80
m/hour.
10/24/13
Newton’s Second Law
Force = Mass X Acceleration
Force (N) = Mass x Acceleration
Force is measured in Newtons
Acceleration of Gravity )Earth) = 9.8 m/s2
Weight (force) = mass x gravity (Earth)
Weight is a measure of the gravitational force that a massive object, such as a star or
planet, puts on another mass.
F=ma
Weight = mass x acceleration of gravity
W=mg m(mass x gravity)
An object’s weight on planet Earth in Newtons is equal to its mass in kilograms
times 9.8m/s2
Mass/Weight
Mass is often confused with weight! It is the amount of material in an object (kg)
Weight is the force of gravity on that. Object and depends where you are!!
Weight
G = 9.8m/s on Earth
G = 1.7 m/s2
Different masses are hung on a spring scale calibrated in Newtons
a.) The force exerted by gravity on 1 kg = 9.8 N