newton’s laws of physics. isaac newton was an english physicist and mathematician who is widely...
TRANSCRIPT
Newton’s Laws of Physics
Isaac NewtonWas an English physicist and mathematician who is widely recognized as one of the most influential scientists of all time and as a key figure in the scientific revolution.
1. An object at rest stays at rest, an object in motion stays in motion unless an external force is applied
(tape on table flat, then roll it)
2. The force is directly proportional to the acceleration and the mass F=ma
(a 2 000kg car to accelerate at 2m/s2 requires what force? F-newtons, m-kg, a-m/s2)
3. Every action has an equal and opposite reaction
(push the wall and fall back)
All three involve forcesTypes of Forces:
Gravitational- pull from Earth
Magnetic- pull or push from a magnet
Electrical- Static Electricity (hair standing up)
Mechanical- push or pull by touching
Fictional- for against motion
Tensile- tightening
Compressive- pushing together
Rotational- turning
Forces have two parts: magnitude and direction
Magnitude- how much of the force is there
Direction- in which way is the force going
Difference between mass and weight
Weight- force of the mass
Mass- how much matter is in the object
Weight = 9.8 x mass
Gravity
Acceleration of Gravity
g = 9.81 m/s2
FrictionStatic Friction- what prevents an object from
moving
Sliding (kinetic) friction- what slows something down once it's moving.
Static friction is greater- that's why we have ABS breaks
We hate sliding friction, it makes us use more force to move things- we use lubricants to reduce the kinetic friction.
Newton’s 2nd Law of Motion
https://www.youtube.com/watch?v=nO7XeYPi2FU
https://www.youtube.com/watch?v=iwP4heWDhvw
Units of measurementForce = N (Newtons)
Mass = kg (kilograms)
Acceleration = m/s2 (meters per second squared)
Example questionWhat net force is required to accelerate a bike at a rate of 3 m/s2 if the bike has a mass of 2,000kg?
F =
m =
a =
HomeworkPage 39: questions 1, 3, 4