Chapter 3 Flashcards
Which philosopherβs teachings dominated science for 2000 years?
Aristotle
Who laid the foundation for modern physical science by discovering the laws of motion and gravitation?
Sir Isaac Newton
What are the branches of physics developed before 1900?
Classical physics
What is a mathematical quantity that has magnitude and direction?
Vector
What type of mathematical quantity only has magnitude?
Scalar
What is an objectβs change in position?
Displacement
What is the effect of combining two or more vectors?
Resultant
What is the study of motion and forces?
Dynamics
What is the branch of physics that addresses he effects of forces on matter?
Mechanics
What is the distance traveled by an object per unit time?
Speed
Formula for Speed
v = π/π‘
What vector measures the displacement of an object per unit of time?
Velocity
Formula for Velocity
π£β= Ξπ₯/t
What is any change in an objectβs velocity, whether increase or decrease in speed or change in direction?
Acceleration
What is the space relative to which motion is measured?
Frame of reference
What law states that the velocity of an object doesnβt change unless the object is acted upon by an external force?
Newtonβs First Law of Motion
What is the other name for the First Law of Motion?
Law of Inertia
What law states that the force required to accelerate an object at a certain rate equals the objectβs mass times the desired acceleration?
Newtonβs Second Law of Motion
Formula for Force
F = ma
What is the SI unit of force?
Newton
What law states that for every action there is an equal and opposite reaction?
Newtonβs Third Law of Motion
How to figure Net Force?
Add or subtract the two forces. Greater force is the direction of the resultant.
What represents the object and forces on it without considering the causes of the forces or the reaction forces exerted by the object?
Free-body diagram
What states that any two objects attract each other through gravitational force?
Law of universal gravitation
Formula for Law of Universal Gravitation
πΉ=πΊ (π_1 π_2)/π^2
What is the gravitational force exerted on an object near the surface of the earth or any celestial body?
Gravity
What is the number commonly accepted as the acceleration of gravity (g)?
9.81 m/s
Formula for Free-fall Distance
d=1/2 ππ‘^2
What is the velocity at which the magnitude of drag equals the objectβs weight and the object stops speeding up?
Terminal Velocity
What is the center-seeking force that causes an object to travel in a curved path rather than a straight line?
Centripetal force
What is an object that hangs from a fixed point and swings back and forth because of gravity?
Pendulum
What type of friction affects sliding objects already in motion?
Kinetic friction
What kind of friction affects stationary objects, preventing them from moving at all?
Static friction
The effect of the surface on friction is called the ________.
Coefficient of friction (π)
Formula for Kinetic Friction Force
F_kf = π_πF_w
What is the transfer of energy from one object to another by a force?
Work
Formula for work
W=fd
What is the SI unit of work?
Joule
What is the rate of doing work?
Power
Formula for Power
P = W/t
What is the SI unit of power?
Watt
What is mathematically described as the product of the objectβs mass and velocity?
Momentum
Formula for momentum
πβ=ππ£β
What are devices for doing work that were devised to multiply muscle power?
Machines
Three main forms of assistance that simple machines provide.
- Multiply applied force
- Multiply the distance
- Change the direction of the force
What is one measure of how much help a machine provides?
Mechanical advantage
What is the multiplication of force by a machine when friction is negligible?
IMA
Formula for IMA
IMA = input distance / output distance
What is a measure of how well a machine converts input work into output work?
Efficiency
Formula for Efficiency
π= π_π/π_π
How are levers classified?
According to where the input and output forces are in relation to the fulcrum.
What happens to the force if an input arm is longer than the output arm of the lever?
The force is multiplied.
What simple machine is similar to a circular lever that multiplies either force or speed?
Wheel and axle
What is a simple machine consisting of a wheel over which a rope or cable passes?
Pulley
What simple machine is a combination of one or more fixed pulleys and one or more movable pulleys?
Block and tackle
What simple machine is a sloping surface that allows an object to be raised without lifting it straight up?
Inclined plane
Formula for IMA
IMA = d_i / d_o = (length/height)
What is a special form of inclined plane that modifies the applied force and directs it to the side?
Wedge
What is the distance from one of the ridges or threads on the screwβs shaft to the next?
Pitch
Formula for IMA of a screw
πΌππ΄= 2ππ/π