# Physics 101 Test 2

nukudaba's version from 2015-10-02 13:00

## Section

Average Acceleration - define - equation - unitsThe rate of change in velocity during a set amt of time - (a = ΔVelocity / Δtime) - m/s^2
Average Speed - Define - equation - unitsRate of speed over a period of time - (s = distance / time) - m/s
Average Velocity - Define - equation - unitsChange in displacement over a set amount of time - (v = Δdisplacement / Δtime) - m/s
Displacement - Define - equation - unitsStraight Line distance from a starting point - Δx = x(f) - f(i) - m
Instantaneous Speed - Define - unitsAverage Speed at a given second - m/s
Acceleration - define - equationchange in velocity in a tiny interval - (Δv/Δt)
Magnitude - Define - EXSize of a vector Qty - Speed is the magnitude of the velocity
Vector - DefineA QTY with a magnitude AND a direction
Velocity - DefineA vector quantity with a speed and a direction
A roller coaster has _ average velocity because _Zero - it returns to the SAME point
Rate of acceleration due to gravity =9.8 m/s^2
Acceleration - Define - unitsRate at which velocity changes - m/s^2
Instantaneous Velocity - Define - UnitsAverage Velocity at a given second - m/s
_ is as important as speed Direction
Speeding up (terms of acceleration)Acceleration and velocity in SAME direction
Slowing down (terms of acceleration)Acceleration and velocity in OPPOSITE directions
Speed is a _ and NOT a _magnitude - Vector
mph/s is a unit of _Acceleration
Amt of acceleration at a CONSTANT speed = _Zero
Constant Acceleration - DefineSpeed changes by SAME amount every second
Kinematics - DefineDescribes the motion of objects
Weight equation(mass)(acceleration due to gravity) OR (m)(g)
Gravity accelerates to the _ of the earthCenter
Force - DefinePush or pull on a body
weightlessness is also called _Free fall
Weight and mass are the Same thing - t OR fFalse
Normal force - Define - Direction of force - UnitForce exerted on a body by a SURFACE - Perpendicular to the Surface and pointing UP Newton (N)
Tension - Define - Direction of force - UnitPulling force exerted by a cable and pointing opposite - Along cable - Newtons (N)
Static Friction - Define - Direction of force -Force EQUAL in SIZE and OPPOSITE in direction to applied force
Kinetic Friction - Define - Direction of force - UnitResistance force between a body and a surface While IN MOTION - Pointing Towards the object that is moving. Placed opposite the direction of motion - Newtons (N)
Applied force - Define - Direction - UnitsForce applied by person - in direction of movement (behind body) - Newton (N)
Newtons 1st law of MotionEvery body continues its state of rest OR uniform speed in a stright line AS LONG AS no net forces act upon it
Newtons 2nd law of MotionThe acceleration of an object is DIRECTLY proportional to the NET FORCES acting on it AND is INVERSELY proportional to it mass
Newtons 2nd motion law equationacceleration = net forces / mass OR a=Σf/m
F(net) EquationForces(net) = (mass) (acceleration) OR F(net) = (m) (a)
Newtons 3rd law of MotionFor every action there s an equal and OPPOSITE reaction
Uniform Circular Motion - definethe motion of an object in a circle at a CONSTANT SPEED.While in circular movement its velocity is CONSTANTLY CHANGING
Centripetal ForceA force which keeps a body moving with a UNIFORM SPEED along a circular path and is directed along the radius towards the center
In a constant circular motion the is a _ change of velocityCONSTANT
Centrifugal Force - DefineForce pulling an object AWAY from the center of a circle
Centripetal Acceleration - Define - Equation - UnitsThe acceleration that is directed TOWARD the center of the circle - centripetal accel. = (body's speed)^2 / radius of circle OR a(c) = v^2 / r - m/s^2
Total acceleration in a Circular Motion - equationtotal accel. = (centripetal accel.) + (tangent accel)
Tangential Acceleration - Define - EquationAccel. component causes a change in the speed (v) of the particle - tan. accel. = ABS(Derivative speed / derivative time)
Derivative - Simple DefinitionChange in magnitude of a force
AN object moving on a FLAT surface with a CONSTANT speed has _ f(net)Zero
F(net) equation is measured in N because _The equation is concerned with the amt. of INERTIA in an object
1 N =Force needed to accelerate 1 kg of mass 1 m/s^2 - (kg)(m/s^2)
f(net) ALWAYS point in _ direction as accelerationSame
Tension forces drawn AWAY from object being _pulled
Static friction is _ than kinetic frictionBIGGER
Kinetic friction has _ value independent of the speed of the objectConstant
Even breaking is_ friction and E-breaking is _ frictionstatic - kinetic
Why does a frog not fall into the earth?The downward force of the frogs weight (N) is EQUAL to the normal forces exerted from the floor going up
Explain Jumping through newtons 3rd law of motionYou exert a downward applied force and the NORMAL force of the floor exerts a force that propels you upward.
Why is recoil from a gun not as strong as the firing bullet?Inertia, the gun has more to the same fore propels the bullet while only slightly moving the gun
All forces occur in _ that are equal and _Pairs - Opposite
(Newtons 3rd law) YOU exert a downward force on the floor and the FLOOR exerts an equal force on you. Do these forces cancel each other out?NO, these forces are equal according to the law BUT they DO NOT have a net force of 0 because they are acting on DIFFERENT objects. Crazy......
A race car gets its centripetal force from the _ between the tires and the floorFriction
Subtracting Vectors - equationΔv = v(f) - v(i)
When adding vectors you can NOT change the _ or the _ of the originalSize (magnitude) - direction
Length of a vector is its _Magnitude
the initial and final vector are drawn _ to _heel - heel
Velocity is in direction of motion and acceleration can point _ or _ the direction of motionTowards - against
When a ball rolling UP a hill are its velocity and acceleration in opposite directions until it starts to move in the opposite directionYes, the acceleration only changes direction once it STARTS to move again
(T or F) as a ball first rolls up a hill and then backwards down the hill, the direction of the acceleration is pointing DOWN the hillTrue, the velocity changes but the acceleration is pointing the same direction the whole time
Is centripetal force a net force? Yes
(T or F) in a uniform circular motion and at a constant speed, the normal force IS the centripetal forceTrue
Do you show centrifugal or centripetal force on a FBD?No, you only show F(normal) f(gravitational) and f(normal). in a sense f(normal) is the centripetal and the other two make up the centrigugal
What determines the speed of a ball being spun on a string?The tension
Projectile motion - DefineA moving object with an initial velocity and near earths surface with ONLY the force of gravity acting on it
Projectile motion is in the shape of a _ equationParabola
Which falls faster, a bullet fired from a gun or a ball dropped from the same height?They fall at the SAME rate
Translation Motion - defineMotion along a path ( ball flying through air)
Rotational Motion - DefineObject spinning around its center of mass (ball spinning while flying through air)
Center of mass - defineThe Point in an object that it will rotate around in a translation of motion
Do transnational and rotational motions affect each other?NO
(T or F) In a 3D motion, The laws for each dimensional motion apply to each dimension separatelyTrue
An object moving in a circular motion, at a constant speed must have a _ acting on itf(net)