3. A 1,000 kg car with a speed of 90.0 km/h brakes to stop. How many cal of heat are generated
by the brakes as a result?
74700 cal or 74.7 kcal
6. A 50.0 g silver spoon at 20.0 C is placed in a cup of coffee at 90.0 C. How much heat does
the spoon absorb

1: How much work is done when a force of 800.0 N is exerted while pushing a crate across a
level floor for a distance of 1.5 m?
W = 1200 j
3: A 5.0 kg textbook is raised a distance of 30.0 cm as a student prepares to leave for school.
How much work did th

1: What is the average speed in km/h of a car that travels 400.0 km in 4.5 h?
400 / 4.5 = 88.89 km/h
5: What is the resulting acceleration when 300 N force acts on acts on an object with a mass of
3,000 kg?
0.1 m/s
6: A boat moves 10.0 km across a lake in

Will a fuel cell be the automobile engine of the future?
The problem with a fuel cell is that it is a thermodynamically open system. What this means is
that the reactants must constantly flow into the cell. This is contrast to a thermodynamically
closed s

1 - A water wave has a frequency of 6 Hz and a wavelength of 3 m.
(a) What is the period of these waves?
166 2/3 ms
(b) What is the wave velocity?
18 Meters per sec
2 - The lower frequency limit for human hearing is usually considered to be 20.0 Hz. What

Chapter 6 Group B:
Problems: 6, 8, 10, 11, and 12
There is a current of 0.83 A through a lightbulb in a 120 V circuit. What is the resistance of this
lightbulb?
R=V/I
= 120 V / 0.83 A
= 144.578 Ohms
A 10.0 lightbulb is connected to a 12.0 V battery. (a) W

Chapter 7 Group B:
Problems: 2, 3, 6, 8, and 9
How much time is required for reflected sunlight to travel from the Moon to Earth
if the distance between Earth and the Moon is 3.85 105 km?
1.28 103 s
How many minutes are required for a radio signal to trav

What applications do the non-visible waves of the electromagnetic spectrum have in your life and work?
Let us get the obvious ones out of the way. We use the EM spectrum to view everything around us with
our eyes. With this said we only use a small portio