Work and Energy
In which of the following scenarios is work done?
A car decelerates while traveling on a flat stretch of road.
In which of the following scenarios is no net work done?
A car travels at a constant speed on a flat road.
The equation for determining gravitational potential energy is PE= mgh. Which factor(s) in this equation is not intrinsic to an object?
Both g and h.
Which of the following energy forms is not involved in hitting a tennis ball?
Chemical potential energy.
Which forms of energy is involved in weighing fruit on a spring scale?
Elastic potential energy.
Which of the following is a form of mechanical energy?
Gravitational potential energy.
Which of the following formulas would be used to directly calculate the kinetic energy of an object with mass m bouncing up and down on a spring constant k?
KE= 1/2mv^2
Why doesn't the principle of mechanical energy conservation hold in situations when frictional forces are present?
Kinetic energy is not completely converted to a form of potential energy.
Which of the following energy forms is associated with an object in motion?
Kinetic energy.
Which of the following refers to the sum of kinetic energy and all forms of potential energy?
Mechanical energy.
What is the unit for a spring constant?
N/m
Which of the following parameters does not depend on how resistant a spring is to being compressed or stretched?
Relaxed length.
In which of the following sentences is work used in the scientific sense of the word?
Sam and Rachel pushed hard, but they could do no work on the car.
In which of the following sentences is work used in the everyday sense of the word?
Sam and Rachel worked hard pushing the car.
Which of the following is a true statement about the conservation of energy?
Total energy is always conserved.
Which of the following equations expresses the work-kinetic energy theorem?
W(net)= Change in KE
Gravitational potential energy is always measured in relation to:
a zero level.
A force does work on an object if a component of the force:
is parallel to the displacement of the object.
The main difference between kinetic energy and potential energy is that:
kinetic energy involves motion and potential energy involves position.
In the presence of frictional force:
non mechanical energy is no longer negligible and mechanical energy is no longer conserved.
Friction converts kinetic energy to:
non mechanical energy.
If the sign if work is negative:
the displacement is the direction opposite of the force.
Work is done when:
the displacement is zero.
