Torque problem: Penguin mobile
A toy "mobile" of penguins hangs motionless. Each cross-bar is horizontal, of negligible
mass & extended 3 times as far to the right of the supporting wire as to the left. Mass of
penguin 1 is 9.6g.
What are the masses of pe
LookingDeeper
Buzzsession:
Howcanweexplainbuoyantforce?
Whathappenstoanobjectwhenyouimmerseit?
Pressure
Duetopressurefromsurroundingfluid,aforce
actsinwardsfromALLdirectionsontheobject.
force
force
force
force
Pressure
Wespeakofthepressureatapointinafl
Buoyancy force ONLY
depends on the
SUBMERGED volume.
ArchimedesPrinciple
Whenanobjectisimmersedina
fluid,thereisanupwardbuoyant
forceequaltotheweightofthe
volumeoffluiddisplacedbythe
object.
Thisappliestoeitherfullor
partialimmersion(i.e.asinking
orfloa
Case Study #2: Falling Down
Look at any of the Sky TV or similar
dishes in pubs, clubs and backyards.
They are supposedly aimed at geostationary
communication satellites in the sky.
But what keeps these satellites up? Why don
t they fall down like every
Homework Set 10: Solutions
Due: Wednesday, December 5, 2012
Chapter 13: Questions
(10) 8 points
A at, uniform cylinder of lead oats in mercury at 0 C. Will the lead oat higher or lower
when the temperature is raised? Explain.
The lead oats in the mercury
OpenStax-CNX module: m42209
1
Viscosity and Laminar Flow;
Poiseuille's Law
OpenStax College
This work is produced by OpenStax-CNX and licensed under the
Creative Commons Attribution License 3.0
Abstract
Dene laminar ow and turbulent ow.
Explain what vis
Physical Constants
Physical constants
symbol
name
c
speed of light in a vacuum
G
gravitational constant
h
planck's constant
h/2
reduced planck's constant
dirac's constant
0
electric constant
permitivitty of free space
vacuum permitivitty
0
magnetic consta
MarineSedimentProxyRecords
WhyStudyOceanWaterTemperature?
Theoceanscoverover70%oftheEarths
surface and influence climate on a global
scale. Heat exchange between the oceans
surfaceandtheatmosphereiscrucialtoboth
oceanic and atmospheric circulation
pattern
Chapter 6 Rotation and Angular Momentum
Chapter 6 Rotation and Angular Momentum
6-1 What Is Physics?
6-2 Equilibrium
6-3 The Rotational Variables
6-4 Are Angular Quantities Vectors?
6-5 Relating the Linear and Angular Variables
6-6 Kinetic Energy of Rotat
Chapter 5 Center of Mass and Linear
Momentum
Source: NASA/JPL-CalTech
Chapter 5 Center of Mass and Linear
Momentum
5-1 What Is Physics?
5-2 The Center of Mass
5-3 Newton's Second Law for a System of Particles
5-4 Linear Momentum
5-5 The Linear Momentum of
1. :
2.
3.
4.
z
P ( x, y , z )
O
X
z
P ( r , ,)
r
O
X
z r cos
r sin
Y
y
x
Y
z
k
1.
r xi yj zk
2 2 2
r | r | x y z
x
y
z
cos , cos , cos
r
r
r
P ( x, y , z )
i
O
r
X
2.
x x(t ), y y (t ), z z (t )
r r (t ) x(t )i
Howcanasteelboatfloat?
2minuteBuzzSession
Drawupalistofthingswhichfloat.
Drawupanotherlistofthingswhichsink.
Ifquestionsarise,writethemdowntoo.
Part of the purpose of this exercise is to bring out
and use what you already know about physics.
Whatallows
Rockslide
During a rockslide, a 520kg rock slides from rest down a hillside 500m long and 300m
high. Coefcient of kinetic friction between the rock and the hill surface is 0.25.
(a) If the gravitational potential energy of the rock-Earth system is set to
Colliding balls
from 1996 exam
A ball of mass 700g is fastened to a cord 800mm long and xed at the far end at a support, and
is released when the cord is horizontal. At the bottom of its path, the ball strikes a stationary
350g ball suspended from the sam
Loop-the-loop
What height does the ball have to start at to make it through the loop?
Let point 1 be where the
1
ball starts, at height x, and
point 2 be at the top of the
loop, at height 2r where r is
the radius of the loop.
2
Solution: Look at point 2 r
Ball changing direction
KJF problem 10.11
A 20 g plastic ball is moving to the left at 30 m/s. How much work must be done
on the ball to cause it to move to the right at 30 m/s?
Solution: Consider the energy of the ball, which is all kinetic.
Initial velo
Dragging a crate
A worker drags a crate across a factory oor by pulling on a rope tied to the crate. The
worker exerts a force of 450N on the rope, which is inclined at 38 to the horizontal, and
the oor exerts a horizontal friction of 125N that opposes th
Box on a slope
A box is held in position by a cable along a smooth slope, as shown. If =60 and m=50
kg, nd the tension in the cable and the normal force exerted by the slope.
Solution: Draw the free-body diagram:
T
N
30
W
W
W
Resolve the forces into direc
Overtaking a truck
(Example 10.17)
Your 1500 kg car is behind a truck travelling at 90 km h1 (= 25 m s1). To pass it,
you speed up to 120 km h1 (33 m s1) in 6.0 s.
What engine power is required to do this?
Solution: The initial kinetic energy of your car
Hitting a cricket ball
A 150g cricket ball is bowled with a speed of 20 ms1. The batsman hits it straight back to
the bowler at 40 ms1, and the impulsive force of bat on ball has the shape as shown.
(a) What is the maximum force the bat exerts on the ball
Tipping box
(2009 exam)
A box, 2.0m tall and 0.5m by 0.5m wide is resting on a at
horizontal surface. The box is pushed by a horizontal
force of magnitude F at a height h above the ground in an
attempt to make the box slide.
If the box is pushed too near
Physics1Fundamental
PRS, QUIZZ and video
PRS, QUIZZ and video
Q2. Now that you know the weight of the container with
the steel marble is the largest, while the others are equal
in weight.
Which of the following descriptions of the `excess
weight of the co
Chapter3 force
3-1 What Is Physics?
3-2 Newtonian Mechanics
3-3 Newton's First Law
3-4 Force
3-5 Mass
3-6 Newton's Second Law
3-7 Newton's Third Law
3-8 Applying Newton's Laws
3-9 Some Particular Forces
3-10 Friction
3-11 The Drag Force and Terminal Speed