2. A body is subject to three forces: F1 = 2^ + 2^ N, i applied at the point x = 2 m, y = 0 m; F2 = -2^ - i 3^ N, applied at x = -1 m, y = 0; and F3 = 1^ N, applied at x = -7 m, y = 1 m. (a) Show explicitly that the n
SYSTEMS OF PARTICLES
y 35 Mg
ActivPhysics can help with these problems: Activities 6.6, 6.7 Section 10-1: Center of Mass Problem
1. A 28-kg child sits at one end of a 3.5-m-long seesaw. Where should her 65-kg father sit so the center of mass wi
HEAT, WORK, AND THE FIRST LAW OF THERMODYNAMICS
750 J of work on its surroundings. By how much does the internal energy of the gas change?
ActivPhysics can help with these problems: Activities 8.58.13 Section 21-1: The First Law of Thermodynami
MOTION IN MORE THAN ONE DIMENSION
3. An object is moving in the x direction at 1.3 m/s when it is subjected to an acceleration given by a = 0.52 m/s2 . What is its velocity vector after 4.4 s of acceleration?
ActivPhysics can help with t
WORK, ENERGY, AND POWER
How much work do you do on the barbell during this time? (c) You lower the barbell to the ground. Now how much work do you do on it?
ActivPhysics can help with these problems: Activity 5.1 Section 7-1: Work Problem
density of the compressed air? (b) How large a volume would the same gas occupy at typical 3 atmospheric density of 1.2 kg/m ?
Section 18-1: Describing Fluids: Density and Pressure Problem
1. The density of molasses is 1600 kg/m .
4. A 25-cm-diameter circular saw blade spins at 3500 rpm. How fast would you have to push a straight hand saw to have the teeth move through the wood at the same rate as the circular saw teeth?
ActivPhysics can help wi
THERMODYNAMICS TEMPERATURE AND HEAT
Temperature dierences on the Fahrenheit and Celsius scales are related by TF = (9/5) TC , so ( 9 ) 5 (10 C ) = 18 F. (Note that a temperature dierence and a temperature reading are not the same, even tho
FORCE AND MOTION
Assume that the seatbelt holds the passenger rmly to the seat, so that the passenger also stops in 0.14 s without incurring any secondary impact. Then the passengers average acceleration is aav = (0 v0 )/t, and the aver
ROTATIONAL VECTORS AND ANGULAR MOMENTUM
ActivPhysics can help with these problems: Activities 7.1, 7.16, 7.17 Section 13-1: Angular Velocity and Acceleration Vectors Problem
1. A car is headed north at 70 km/h. Give the magnitude and direction
an average impulsive force of 1.2105 N acts for 0.25 s? (b) If the car's mass is 1800 kg, for what initial speed would this collision bring the car to a stop?
ActivPhysics can help with these problems: Activities 6.26.6 Section 11-1:
radius. Thus, R/RE = 1/ 3 = 57.7% gives the new, shrunken radius.
ActivPhysics can help with these problems: Activity 4.8 Section 9-2: The Law of Universal Gravitation Problem
1. Space explorers land on a planet with the same mass a
CONSERVATION OF ENERGY
Take the origin at point 1 in Fig. 8-26 with the x-axis horizontal to the right and the y-axis vertical upward. The gravitational force on an object is constant, Fg = mg, while the paths are (a) dr = dy for x = 0
USING NEWTONS LAWS
2T cos 25 Fres = max , since T1 = T2 = T. (a) If ax = 0, Fres = 2(1100 N) cos 25 = 1.99 kN. 2 (b) If ax = 0.16 m/s , Fres = 1.99 kN (3700 kg) (0.16 m/s2 ) = 1.40 kN.
ActivPhysics can help with these problems: All Activities in
THE VECTOR DESCRIPTION OF MOTION
3. A migrating whale follows the west coast of Mexico and North America toward its summer home in Alaska. It first travels 360 km due northwest to just off the coast of Northern California and then turns
MECHANICS MOTION IN A STRAIGHT LINE
course in 2 h 12 min 36 s. What was Thugwame's average speed, in meters per second?
ActivPhysics can help with these problems: Activities 1.21.9 Section 2-1: Distance, Time, Speed, and Velocity Problem
THE SECOND LAW OF THERMODYNAMICS
(a) There are 2 directions for each molecule, so the number of states is 24 = 16. (b) Two of these, all to the right or all to the left, have all molecules moving in the same direction. (c) If all state
THE THERMAL BEHAVIOR OF MATTER
4. An ideal gas occupies a volume V at 100 C. If the gas pressure is held constant, by what factor does the volume change (a) if the Celsius temperature is doubled and (b) if the kelvin temperature is doub
SOUND AND OTHER WAVE PHENOMENA
How many miles away did the ash occur? Neglect the travel time for the light (why?)
ActivPhysics can help with these problems: Activities 10.3, 10.4, 10.5, 10.6, 10.8, 10.9 Sections 17-1 and 17-2: Sound Waves and
1.25 m apart. What is the speed of the waves on the cable? Compare with the speed of light in vacuum.
ActivPhysics can help with these problems: Activities 10.1, 10.2, 10.7, 10.10 Section 16-2: Wave Properties Problem
1. Ocean waves
Physics 101 Fall 2007: Pledged Problems 8 System of Particles & Momentum
Time allowed: 2 hours in one sitting Due: Monday, November 5 at 5PM in the box marked Phys101/102 in the Physics Lounge You may use your own textbook, your notes and a non-programmed
Physics 8a Section 110 Practice Midterm #1 Solutions: 1. Choose up as +y:
a. b. c. hmax = h + a h g
Known: a = 5.00 m/s^2 g = 9.8 m/s^2 h = 2000 m
v f = 2 ghmax The gass momentum changes as it leaves the rocket and this change in momentum corresponds to a
OSCILLATIONS, WAVES, AND FLUIDS OSCILLATORY MOTION
cos[(10 s1 )t]. (b) The maximum (positive) velocity occurs at t = 0 if sin = 1 (from Equation 15-10), therefore, the motion is described by Equation 15-9 with A = 2.5 cm, = 5 s1 , and = /2. Since c