Chapter 4
A single force acts on an object. The components of this force act along the +x-axis and the -y-axis. The single force that will bring the object into equilibrium has components that act along the
-x-axis and +y-axis.
A net force of 6.8 N accelerates a 31 kg scooter across a level parking lot. What is the magnitude of the scooter's acceleration?
0.22 m/s2
A waitperson carrying a tray with a platter on it tips the tray at an angle of 12 degrees below the horizontal. If the gravitational force on the platter is 5.0 N, what is the magnitude of the force parallel to the tray that tends to cause the platter to slide down the tray?
1.0 N
A 100-N lantern is suspended by a pair of ropes with 120 degrees between them (each 60 degrees from the vertical). The tension in each rope is
100 N
An airplane with a mass of 1.20 x 10^4 kg tows a glider with a mass of 0.60 x 10^4 kg. If the airplane propellers provide a net forward thrust of 3.60 x 10^4 N, what is the acceleration of the glider?
2.00 m/s^2
What is the minimum resultant possible when adding a 5-N force to an 8-N force?
3 N
In the free-body diagram shown above, which of the following is the gravitational force acting on the balloon?
4050 N
A ball is dropped from a person's hand and falls to Earth. Identify an action-reaction pair in this situation.
Earth exerts a force on the ball; the ball exerts a force on Earth
Which of the following statements does not describe force?
Force causes objects at rest to remain stationary
An object is at rest suspended from two cables. Which of the following properly describes the forces involved?
The forces acting upward and downward on the object are balanced
A hammer drives a nail into a piece of wood. Identify an action-reaction pair in this situation.
The hammer exerts a force on the nail;the nail exerts a force on the hammer
A leaf falls from a tree and lands on the sidewalk. Identify an action-reaction pair in this situation.
The leaf exerts a force on the sidewalk; the sidewalk exerts a force on the leaf
A hockey stick hits a puck on the ice. Identify an action-reaction pair in this situation.
The stick exerts a force on the puck; the puck exerts a force on the stick
Which of the following descriptions best describes an object at rest on a table?
The support force is equal to the object's weight
A free-body diagram of a ball falling in the presence of air resistance would show
a downward arrow to represent the force due to gravity and an upward arrow to represent the force of air resistance
A small force acting on a human-sized object causes
a small acceleration
Which are simultaneous equal but opposite forces resulting from the interaction of two objects?
action-reaction pairs
If a nonzero net force is acting on an object, then the object is definitely
being accelerated
Which of the following forces arises from direct physical contact between two objects?
contact force
Which of the following forces exists between objects even in the absence of direct physical contact?
field force
The Newton is the SI unit for what physical quantity?
force
What causes a moving object to change direction?
force
Which of the following is the cause of an acceleration?
force
Which of the following statements does not describe force?
force causes objects at rest to remain stationary
A free-body diagram represents all of the following except?
forces exerted by the objects
Which of the following forces is an example of a contact force?
frictional force
Which of the following forces is an example of a field force?
gravitational force
As a basketball player starts to jump for a rebound, the player begins to move upward faster and faster until his shoes leave the floor. At a moment the player begins to jump, the force of the floor on the shoes is
greater than the player's weight
Which of the following is the tendency of an object to maintain its state of motion?
inertia
A newton is equivalent to which of the following?
kg x m/s^2
The length of a force vector represents the
magnitude of the force
A measure of the quantity of matter is
mass
What term is used to describe the vector sum of all forces acting on an object?
net force
Which statement about the acceleration of an object is correct?
the acceleration of an object is directly proportional to the net external force acting on the object and inversely proportional to the mass of the object
The free-body diagram shown above represents a car being pulled by a towing cable. In the diagram, the 5800 N force is
the force exerted by the towing cable on the car
According to Newton's second law, when the same force is applied to two objects of different masses,
the object with greater mass will experience a smaller acceleration and the object with less mass will experience a greater acceleration.
As an object falls toward Earth,
the upward acceleration of Earth is negligible because of its large mass.
The statement by Newton that for every action there is an equal but opposite reaction is which of his laws of motion?
third
Newton's third law of motion involves the interactions of
two objects and two forces
A change in the force of gravity acting on an object will affect the object's
weight
The magnitude of the gravitational force acting on an object is
weight
A car goes forward along a level road at a constant velocity. The additional force needed to bring the car into equilibrium is
zero
A car goes forward along a level road at constant velocity. The additional force needed to bring the car into equilibrium is
zero
