A space explorer is moving through space in the middle of intergalactic space, very far
from any planet or star. He notices a large rock floating around the cabin of the ship. The
explorer wishes to take it as a specimen from an alien planet. Should he pu
8.) A mass m at the end of a spring vibrates with a frequency of 0.88 Hz. When an
additional 680-g mass is added to m, the frequency is 0.60 Hz. What is the value of m?
m = = 0.52 kg
14.) It takes a force of 80.0 N to compress the spring of a t
2.) A is gas enclosed in a cylinder fitted with a light frictionless piston and maintained at
atmospheric pressure. When 1400 kcal of heat is added to the gas, the volume is observed
to increase slowly from 12.0 m3 to 18.2 m3. Calculate (a) the
10.) A 3800-kg open railroad car coasts along with a constant speed of 8.60 m/s on a level
track. Snow begins to fall vertically and fills the car at a rate of 3.50 kg/min. Ignoring
friction with the tracks, what is the speed of the car after 90
12.) Find the tension in the two wires supporting the traffic light shown in Fig. 9-46.
Weight of Light = 30 kg * 9.8 m/s2 = 294 N; T1 is for wire on Left and T2 is for wire on right:
T1 = = 235 N T2 = = 177 N
13.) How close to the edge of the 2
8.) Vector V1 is 6.6 units long and points along the negative x axis. Vector V2 is 8.5 units long
and points at +45 to the positive x axis. (a) What are the x and y components of each
vector? (b)Determine the sum V1 + V2 (magnitude and angle).
Problem 1: One lightyear is defined to be the distance light can travel in one year.
a. What is this distance in meters?
1 lightyear = 365 days * 86400 seconds * 3x10^8 meters/second
1 lightyear = 9460730472580800 meters ~ 9.46x10^15 meters
b. How long do
8.) A 0.45-kg ball, attached to the end of a horizontal cord, is rotated in a circle of radius 1.3
m on a frictionless horizontal surface. If the cord will break when the tension in it exceeds
75 N, what is the maximum speed the ball can have?
A stone is thrown horizontally with an initial speed of 10 m/s from the edge of a cliff. A stop
watch measures the stone's trajectory time from the top of the cliff to the bottom to be 4.3 s. What
is the height of the cliff?
A) 77 m
B) 22 m
C) 43 m
Use the conservation of energy law to explain why the temperature of a gas increases when
it is quickly compressed, whereas the temperature decreases when the gas expands.
When a gas is quickly compressed, work is done on it. This changes the internal ene
Mammals that depend on being able to run fast have slender lower legs with flesh and
muscle concentrated high close to the body. On the basis of rotational dynamics, explain
why this distribution of mass is advantageous.
This involves the moment of inerti
The gravitational force on the Moon due to the earth is only about one half the force on the
Moon due to the sun. Why isnt the Moon pulled away from the Earth?
Newtons law of universal gravitation applies to this. All objects attract all other objects
2.) How does the number of atoms in a 26.5-gram gold ring compare to the number in a
sliver ring of the same mass?
Ng = 0.135(6.023x1023) = 8.13x1022
Gold: n = = 0.135
Silver: n = = 0.246
Ns = 0.246(6.023x1023) = 1.48x1023
There are jus
T (at t = 2.54 s) =
When the system is at rest, the net forces act on individual bodies should balance each other.
Diagrams on the individual bodies:
On the first body
T = W1
T = (1)g
- ( 1 )
On the second body,
T + FN = W 2
T + FN = (1.1)g
The introduction of air resistance made a lot of difference here. In the first two
simulations, no difference occurred because the mass of the ball did not change the effect of
gravity on it. In this third simulation, the potential energy before the ball
Roofs of houses are sometimes blown off during a tornado or hurricanes. Explain this
using Bernoullis Principle.
Bernoullis Principle states that where the velocity of a fluid is high, the pressure is low,
and where the velocity is low, the pressure is hi
If an equation is dimensionally correct, does this mean that the equation must be true? If
an equation is not dimensionally correct, does this mean that the equation cannot be true?
No. Just because an equation is dimensionally correct does not m
Will a grandfather clock (a pendulum clock), accurate at 20C, run fast or slow on a hot
day (say 30C)? Explain.
The increase in temperature, heat, will cause the brass rod to expand and therefore
lengthen. With a longer pendulum swing, the clock will run
1.) The age of the universe is thought to be about 14 billion years. Assuming two significant
figures, write this in powers of 10 (a) years, (b) seconds.
a.) 1.4x1010 years
b.) 1.4x1010(365 days)(24 hours)(60 minutes)(60 s) = 4.4x1017 s