Physics 1: Kinematics, Energy, Momentum, Work Flashcards
Forces are vectors required to change _____ and can be caused by any push or pull.
velocity
Examples of push/pull forces used to change velocity
Gravity
Friction
Rotation
_____, like Forces, are vectors that can cause a change in velocity. Net ____ must be equal to 0 to maintain equilibrium.
Torques
Forces that act over a distance
Represents a change in energy
work
May be converted from kinetic to potential and back but total value must always be conserved
energy
even if some energy is lost to the environment, _____ is always conserved in collisions
momentum
VAT Kinematic Equation
Vf = Vo + a*t
VAX Kinematic Equation
Vf^2 = Vo^2 + 2ax
VTAX Kinematic Equation
x = Vo * t + 1/2 * a * t^2
Uniform Acceleration Equation
x = 1/2 (Vo + Vf) * t
Equation: When PE completely converted to KE
V^2 = 2gh
Definition: Newton’s First Law
Inertia
an object in motion (or at rest) will stay in motion (or at rest) unless acted on by a net outside force
Definition: Newton’s Second Law
To change velocity, you need a Force, which produced acceleration
When does acceleration = 0?
when an object is not moving
when velocity is constant
SI Unit: Force
Newtons = kg*m/sec^2
A falling object accelerating due to gravity will encounter air resistance _________ to its increasing velocity
proportional
At terminal velocity, the air resistance equals _______, resulting in no Fnet and no acceleration
force of gravity
Definition: Newton’s Third Law
Every action has an equal and opposite reaction
Force pairs must be the same TYPE of force (i.e. Gravity, Normal Force)
Newton’s Third Law only applies to gravity when?
If you enlarge the system to include to include the source of gravity, i.e. the Earth itself
The force exerted by a surface that opposes
acts perpendicular to the surface
Normal Force
If F(net) = 0, and the only other force acting on the object is gravity, then the magnitude of the normal force (Fn) = ?
F(g) = m*g
*Note: g = accel due to gravity= ~10 m/s^2
If an elevator is accelerating upward, F(n) also includes opposition to the force of upward acceleration (m*a), so F(n) = ?
F(n) = ma + mg
If an elevator is accelerating downward, F(n) = ?
F(n) = ma - mg
A weight scale measures ______
the normal force
tendency of objects to stick together, opposing new forces
opposes movement
Friction
type of friction between two objects that are sitting still
varies w/ the force applied
has an absolute maximum, after which motion occurs and this value drops to zero
static friction
type of friction between moving objects
proportional ONLY to the Normal force, not the force applied
kinetic friction
tendency of masses to attract other masses
force is always attractive
gravity
Equation: Force due to gravity
F(g) = G m1 * M2 / r^2 = mg
Note: G-gravitational constant; g = accel due to g; M-mass of earth; m-mass of object; r-radius of Earth from center to surface
sin(0)
= 0 (square root 0/2)