PHY 121 Exam Practice Questions with
Verified Correct Answers
A jet plane is speeding down the runway during takeoff. Air resistance is not negligible,
friction is negligible.
Identify the forces on the jet.
Normal force ->n
Force of thrust ->F thrust
Drag ->F Drag
Gravity force ->F G
In Figure 1, block B is falling and dragging block A across a table.
How many force vectors would be shown on a free-body diagram of block A?
4
In Figure 1, block B is falling and dragging block A across a table.
Name the forces on block A.
Friction the surface
Gravity
Normal
Tension
An object at rest cannot remain at rest unless which of the following holds?
The net force acting on it is zero.
If a block is moving to the left at a constant velocity, what can one conclude?
, The net force applied to the block is zero.
A block of mass 2kg is acted upon by two forces: 3N (directed to the left) and 4N
(directed to the right). What can you say about the block's motion?
It could be moving to the left, moving to the right, or be instantaneously at rest.
A massive block is being pulled along a horizontal frictionless surface by a constant
horizontal force. The block must be __________.
moving with a constant nonzero acceleration
Two forces, of magnitude 4N and 10N, are applied to an object. The relative direction of
the forces is unknown. The net force acting on the object __________.
cannot have a magnitude equal to 5N
For Figure 2, Select the correct direction of the acceleration vector a for the system
Down
For Figure 2, Select the correct direction of the velocity vector v.
Down
For Figure 2, Select the correct description of a real object for which this is the correct
free-body diagram.
A ball dropped by Galileo from the Leaning Tower of Pisa.
Two cars start from rest and race down a track of 1000 m. Both cars have the same
mass of 2000 kg. Car #1 can accelerate with a net force of 1400 N. Car #2 can accelerate
with a net force of 2000 N. How do the times t1 and t2 for each car compare?
t1/t2 = 1.2
Verified Correct Answers
A jet plane is speeding down the runway during takeoff. Air resistance is not negligible,
friction is negligible.
Identify the forces on the jet.
Normal force ->n
Force of thrust ->F thrust
Drag ->F Drag
Gravity force ->F G
In Figure 1, block B is falling and dragging block A across a table.
How many force vectors would be shown on a free-body diagram of block A?
4
In Figure 1, block B is falling and dragging block A across a table.
Name the forces on block A.
Friction the surface
Gravity
Normal
Tension
An object at rest cannot remain at rest unless which of the following holds?
The net force acting on it is zero.
If a block is moving to the left at a constant velocity, what can one conclude?
, The net force applied to the block is zero.
A block of mass 2kg is acted upon by two forces: 3N (directed to the left) and 4N
(directed to the right). What can you say about the block's motion?
It could be moving to the left, moving to the right, or be instantaneously at rest.
A massive block is being pulled along a horizontal frictionless surface by a constant
horizontal force. The block must be __________.
moving with a constant nonzero acceleration
Two forces, of magnitude 4N and 10N, are applied to an object. The relative direction of
the forces is unknown. The net force acting on the object __________.
cannot have a magnitude equal to 5N
For Figure 2, Select the correct direction of the acceleration vector a for the system
Down
For Figure 2, Select the correct direction of the velocity vector v.
Down
For Figure 2, Select the correct description of a real object for which this is the correct
free-body diagram.
A ball dropped by Galileo from the Leaning Tower of Pisa.
Two cars start from rest and race down a track of 1000 m. Both cars have the same
mass of 2000 kg. Car #1 can accelerate with a net force of 1400 N. Car #2 can accelerate
with a net force of 2000 N. How do the times t1 and t2 for each car compare?
t1/t2 = 1.2
