Chapter 01: Basic Physics for the Respiratory Therapist Cairo:
Mosby’s Respiratory Care Equipment, 10th Edition
MULTIPLE CHOICE
1. Power is a
... [Show More] measure of which of the following?
a. Mechanical energy
b. Gravitational potential energy
c. The rate at which work is being performed
d. The rate at which atoms and molecules move
ANS: C
Power is a measure of the rate at which work is being performed. The formula P = W/J, where W
= watts and 1 watt is equal to 1 J/s, expresses this. Joules are the international standard for
expressing energy and work.
PTS: 1 REF: Page 3
2. When effort produces a change in the position of matter
a. work is performed.
b. it is known as a joule.
c. mechanical power is created.
d. the law of the conservation of energy is being used.
ANS: A
Work is performed only when effort or outside forces produce a change in the position of matter.
PTS: 1 REF: Page 3
3. The unit used to express the force of 1 N acting on a 1-kg object to move it 1 m is which
of the following?
TEST BANK
Mosby’s Respiratory Care Equipment,
10th Edition
a. Watt
b. Joule
c. Kilowatt
d. Kinetic energy (KE)
ANS: B
One joule is equal to the force of 1 N acting on 1 kg. A watt is equivalent to 1 J/s. A kilowatt is
simply 1000 W. KE is energy an object possesses when it is in motion.
PTS: 1 REF: Page 3
4. Power is expressed in which of the following units?
a. Newtons
b. Joules
c. Ohms
d. Watts
ANS: D
Power is a measure of the rate at which work is being performed. Energy and work are measured
in joules. One joule is the force of 1 N acting on a 1-kg object to move it 1 m. Ohms is the
resistance an electrical circuit possesses.
PTS: 1 REF: Page 3
5. Four horsepower (hp) is equal to how many kilowatts (kW)? a. 5.36
b. 2.98
c. 2984
d. 186.5
ANS: B
1 hp = 0.746 kW.
1 hp/0.746 = 4 hp/X.
X = 4 0.476 = 2.98 kW.
PTS: 1 REF: Page 3
6. The energy that an object possesses when it is in motion is called
a. sound.
b. kinetic.
c. thermal.
d. potential.
ANS: B
KE is the energy an object possesses when it stays in motion. Potential energy is stored energy,
and it exists in many forms such as thermal energy or sound waves.
PTS: 1 REF: Page 4
7. If the velocity of an object is reduced by half, its KE will be which of the following?
a. Reduced to one-eighth
b. Increased twofold
c. Reduced twofold
d. Not changed
ANS: A
Kinetic energy = 1/2(mass of object square of velocity it is traveling, or mv2) or KE = 1/2(V
V). If the velocity is reduced by half, then KE = 1/2(1/2V 1/2V), or 1/2(1/2) = 1/8
reduction.
PTS: 1 REF: Page 4
8. Energy that is stored in an object is called which of the following?
a. Kinetic
b. Potential
c. Chemical
d. Mechanical
ANS: B
Energy that is stored or possessed by an object because of its position is called potential energy.
Mechanical energy can be divided into either KE or potential energy. Chemical potential energy
often refers to the bonds in petroleum oils that, if broken, can be converted to KE.
PTS: 1 REF: Page 4
9. The potential energy of a compressed spring is known as which of the following?
a. Gravitational
b. Chemical
c. Inelastic
d. Elastic
ANS: D
The potential energy stored in a compressed spring is called elastic potential energy. This energy
is released when the spring is allowed to uncoil. Gravitational potential energy is the energy an
object possesses if it is held above any surface, energy that the object’s weight gains as it falls.
Chemical potential energy resides in the chemical bonds of the atoms that make up the object.
Inelastic potential energy would not apply once the spring is compressed [Show Less]