# Shared Flashcard Set

## Details

Physic's
Physic's exam 1
65
Physics
03/21/2010

Term
 average speed
Definition
 distance traveled/time takend/t
Term
 distance traveled
Definition
 average speed X time taken
Term
 Velocity equal speed with a direction
Definition
Term
 average velocity
Definition
 change in position/time taken
Term
 average acceleration
Definition
 change in velocity/time taken
Term
 the velocity of an object remains constant unless an unbalanced for
Definition
 Newtons 1st law
Term
 kinetic energy
Definition
 KE=1/2mv^2
Term
 What is the kinetic energy of an 86 kg sprinter running at 11 m/s?
Definition
 5203 Jformla: KE=1/2mv^2
Term
 work
Definition
 work=forceXdistance moved
Term
 gravitional potential energy
Definition
 GPE= (mass)(gravity)(height)
Term
 mechanical energy
Definition
 is the same as KE+GPEwitch is =1/2mv^2+mgh
Term
 power
Definition
 energy converted/time taken
Term
 A 0.5 kg air-hockey puck is initially at rest. What will its kinetic energy be after a net force of 0.6 N acts on it for a distance of 0.4 m?
Definition
 .24 J
Term
 A 15 N block lifted straight upward by a hand applying a force of 15 N has an initial kinetic energy of 8 J. If the block is lifted 2 m, how much work does the hand do?What is the block's final kinetic energy?
Definition
 30 J30J
Term
 The Earth, which orbits the Sun in an elliptical path, reaches its closest point to the Sun on about January 4 each year. Will the work done by the gravitational force of the Sun on the Earth be positive, negative, or zero over the next 6 months?Will the work done be positive, negative, or zero over the next year?
Definition
 The work done will be negative The work done will be zero
Term
 A woman with a mass of 65 kg climbs a set of stairs that are h = 2 m high. How much gravitational potential energy does she gain?
Definition
 1300 J
Term
 A baseball (mass = 145 g) is thrown straight upward with kinetic energy 10.15 J. (a) When the ball has risen 7 m, find the work done by gravity. (Take g = 10 m/s2)(b) Find the ball's kinetic energy. (c) Find the ball's speed.
Definition
 (a)-10.15 J (b)0 J(c)0 J
Term
 What is the gravitational potential energy of a ball with a weight of 58 N when it is sitting on a shelf 1.8 m above the floor?
Definition
 104.4 J
Term
 If a 0.6 kg ball is dropped from a height of 9 m, what is its kinetic energy when it hits the ground?
Definition
 54 J
Term
 Rotational acceleration
Definition
 a=w/tex. 200rpm-500rpm/60mins ans= -5rpm/mins
Term
 Rotational acceleration (remember change the sign to the opposite)
Definition
Term
Definition
 57 degrees
Term
 torque
Definition
Term
 The angular velocity of an object remains constant unless acted on by an unbalanced torque
Definition
 Newtons 1st law of rotation
Term
 The net torque on an object is equal to its rotational inertia times it rotational acceleration
Definition
 Newtons 2nd law of rotation
Term
 formula for rotational kinetic energy is same as the one for kinetic energy
Definition
Term
 angular momentum
Definition
 rotational inertia X rotational speed
Term
 If the beaters on a Mixmaster make 890 revolutions in 3 minutes, what is the average rotational speed of the beaters? Express your answer in both revolutions per minute and revolutions per second.
Definition
 296.6 rev/min4.94 rev/s
Term
 What is the rotational speed of the minute hand on a clock?
Definition
 2.78e-4 rev/s
Term
 If the rotational speed of a CD changes from 700 rpm to 275 rpm as it plays 30 minutes of music, what is the CD's average rotational acceleration?
Definition
 -14.16 rev/min2
Term
 You are holding a 30 kg dumbbell straight out at arm's length. Assuming your arm is 0.72 m long, what torque is the dumbbell exerting on your shoulder?
Definition
 216 N·m(just add a decimal point)
Term
 Two children with masses of 21 and 43 kg are sitting on a balanced seesaw. If the lighter child is sitting 3 m from the center, where is the heavier child sitting?
Definition
 1.46 m from the center(set up a ratio)
Term
 What mass would you hang on the right side of the system in the figure to balance it -- that is, to make the clockwise and counterclockwise torques equal? (Let x1 = 36 cm and x2 = 20 cm.)
Definition
 90 g
Term
 A child with a mass of 55 kg is riding on a merry-go-round. If the child has a speed of 3 m/s and is located 1.3 m from the center of the merry-go-round, what is the child's angular momentum?
Definition
 214.5 kg·m2/s
Term
 the laws of physics are the same in all inertail reference systems
Definition
 principle of relativity
Term
 A spring gun fires a ball horizontally at 12 m/s. It is mounted on a flatcar moving in a straight line at 25 m/s. (a) Relative to the ground, what is the horizontal speed of the ball when the gun is aimed forward?(b) Relative to the ground, what is the horizontal speed of the ball when the gun is aimed backward?
Definition
 (a)37 m/s(b)13 m/s
Term
 An aircraft carrier is moving to the north at a constant 21 mph on a windless day. A plane requires a speed relative to the air of 145 mph to take off. (a) How fast must the plane be traveling relative to the deck of the aircraft carrier to take off if the plane is headed north?(b) How fast must the plane be traveling relative to the deck if the plane is headed south?
Definition
 (a)124 mph(b)166 mph
Term
 Find the value that an observer would measure for the magnitude and direction of the free-fall acceleration in an elevator near the surface of the Earth if the elevator is accelerating downward at each of the following rates. (a) 5 m/s2
Definition
 5 m/s2 downward
Term
 the laws of physics are the same in all intertial systems
Definition
 first postulate of special reativitly
Term
 The speed of light in a vacuum is costant regardless of the speed of the source or this speed of the obsever
Definition
 2nd postulate of special relativity
Term
 speed of light
Definition
 300,000,000
Term
Definition
 1/√1-((v)(c)/c)^2
Term
 relativistic Times
Definition
 know speed of light X microseconds
Term
 L/y
Definition
Term
 yL
Definition
Term
 What is the size of the adjustment factor for a speed of 0.5 c?
Definition
 1.15
Term
 pressure
Definition
 force/area
Term
 P=F/A=6000N/2m^2=3000N/m^2
Definition
Term
 Kelvin
Definition
 =C+273
Term
 Ideal gas laws
Definition
 PV=nRT
Term
 Given that the carbon atom has a mass of 12 amu, how many carbon atoms are there in a diamond with a mass of 1 g?
Definition
 5.02e22 atoms
Term
 About how many atoms would it take to deposit a single layer on a surface with an area of 3 cm2? (Assume the atom has a cross sectional area of A = 1 10-20 m2.)
Definition
 3e16 atoms
Term
 You exert a force of 20 N on the head of a thumbtack. The head of the thumbtack has a radius of 4 mm. What is the pressure on your thumb?
Definition
 3.94 atm
Term
 density
Definition
 mass/volume
Term
 Solving For Volume
Definition
 m/d
Term
 Mass
Definition
 v x D
Term
 Archimedes' principle
Definition
 the buoyant force is equal to weight of the weight of the displaced fluid
Term
 An object has a mass of 290 kg and a volume of 0.4 m3. What is its average density?Will this object sink or float in water?
Definition
 725 kg/m3float
Term
 A solid ball with a volume of 0.1 m3 is made of a material with a density of 3180 kg/m3. What is the mass of the ball?
Definition
 318 kg
Term
 What is the mass of a lead sinker with a volume of 9 cm3?
Definition
 101.7 g
Term
 if objects A and B are in thermal equilibrium with object C, then A and B are in thermal equilibrum with eachother
Definition
 zeroth law thermodynamics
Term
 the increase in the internal energy of a system is equal to the heat added plus the work done on the system
Definition
 1st law of thermodynamics
Term
 Absolute zero may be approached experimentally but can never be reached
Definition
 3rd law of thermodynamics
Term
 Thermal Expansion
Definition
 ΔL=aLΔT
Term
 ΔL=aLΔT=(.000011/*C)(50m)(40*C)=0.022m
Definition
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