exams Guaranteed A+ Self-Assessment
Questions & Verified Correct answers (2025 /
2026)
A ball of mass 0.4 kg is initially at rest on the ground. It is kicked and leaves the kicker's foot
with a speed of 5.0 m/s in a direction 60° above the horizontal. The magnitude of the impulse
imparted by the ball to the foot is most nearly - correct answer✔✔2 N*s
A force of constant magnitude F and fixed direction acts on an object of mass m that is initially
at rest. If the force acts for a time interval ∆t over a displacement ∆x , what is the magnitude of
the resultant change in the linear momentum of the object? - correct answer✔✔FΔt
A person applies an impulse of 5.0 kg∙m/s to a box in order to set it in motion. If the person is in
contact with the box for 0.25 s, what is the average force exerted by the person on the box? -
correct answer✔✔20.0N
An object of known mass M with speed vo travels toward a wall. The object collides with it and
bounces away from the wall in the opposite direction in which the object was initially traveling.
The wall exerts an average force Fo on the object during the collision. A student must use the
equation \Delta p=F\Delta tΔp=FΔt to determine the change in momentum of the object from
immediately before the collision to immediately after the collision. Which side of the equation
could the student use to determine the change of the object's momentum? - correct
answer✔✔Neither side of the equation may be used because there are too many unknown
quantities before, during, and after the collision.
In an experiment, an object is released from rest near and above Earth's surface. A student must
determine the relationship between the direction of the gravitational force exerted on the object
and the change in momentum caused by that force. What data could the student collect to
determine the magnitude and direction of the gravitational force and the change in momentum of
the object? Justify your choices. Select two answers. - correct answer✔✔The mass of the object,
because it is required to determine the force due to gravity exerted on the object, and the velocity
of the object the instant before it reaches Earth's surface, because it is required to determine the
change in velocity of the object.
, The mass of the object, because it is required to determine the force due to gravity exerted on the
object, and the distance fallen by the object, because the force is exerted during the entire falling
distance.
A student conducts an experiment in which an object travels across a horizontal surface while for
2s a net force is applied to a 2 kg object that initially travels with a speed of 0.5 m/s. Data
collected from the experiment are used to create the graph of the magnitude of the applied force
exerted on the object as a function of time is shown. All frictional forces are considered to be
negligible. Can the student use the graph and the known data to determine the momentum of the
object after the force has been applied? - correct answer✔✔No, because the student needs to
know the direction that the force is applied to the object because the applied force will be in the
same direction as the change in momentum of the object.
Cart A with a mass of 2.0 kg travels at a constant speed of 3.0 m/s to the right on a horizontal
surface, as shown in the figure. Cart A then collides with cart B with a mass of 1.5 kg that is
initially at rest... - correct answer✔✔Equation 1 and Equation 2
An object of mass 2 kg collides with an object of mass 1 kg that is at rest, as shown in the figure.
A graph of the force as a function of time that the 1 kg object exerts on the 2 kg object is shown.
- correct answer✔✔(2 kg) (2m/s-v0)=1/2(8000 N)(0.00125 s)
How does an air mattress protect a stunt person landing on the ground after a stunt? - correct
answer✔✔It lengthens the stopping time of the stunt person and reduces the force applied during
the landing.
Ball X of mass 1.0 kg and ball Y of mass .5 kg travel toward each other on a horizontal surface...
- correct answer✔✔ball Y will travel at a speed greater
Assume that the collision in each scenario is elastic. A graph of the magnitude of the force
exerted on Cart Y as a function of time for scenario 1 is shown. During which interval of time
does the magnitude of the momentum of Cart Y change the most? - correct answer✔✔.004s to
.006s
A student drops an object from rest above a force plate that records information about the force
exerted on the object as a function of time during the time interval in which the object is in
contact with the force plate. Which of the following measurements should the student take, in
addition to the measurements from the force plate, to determine the change in momentum of the