BYU Physics 121 Chapter 7 Conceptual
Questions and answers 100% correct
2025
A farmhand carrying a 5 kg bucket of milk dashes 5 meters across a barnyard
at a constant speed of 4 m/s. How much work was done on the bucket in that
process? - correct answer ✔There is no change in kinetic energy, so there is
no work done on the bucket. The gravitational force is perpendicular to the
displacement.
A book is moving to the right across a table at constant speed. There are four
forces acting on it, its weight, W, which is straight down, the normal force of
the table, N, which is straight up, and two applied forces, one, called F1,
pointing 60º to the right of vertical and the other, F2, pointing 60º to the left of
vertical. List each of these forces in the order of increasing work, i.e. first list
the force which does the least work, then the second most, until you reach the
one that does the most work. Two forces that do equal work should have an
equal sign between them. Note that we are asking for the ranking to be done
by the amount of work, not by the magnitude of the amount of work. - correct
answer ✔F2 < W = N < F1
A ball is falling through the air. It has just two forces acting on it, its weight and
air resistance. Which of the following statements is true? - correct answer
✔There are both conservative and nonconservative forces acting on the ball.
All of the following statements are true except one. Which one is false? -
correct answer ✔a. Work done by a conservative force only depends on the
initial and final states.
b. One can never associate a potential energy function with a conservative
force.
c. An example of a nonconservative force is friction.
Questions and answers 100% correct
2025
A farmhand carrying a 5 kg bucket of milk dashes 5 meters across a barnyard
at a constant speed of 4 m/s. How much work was done on the bucket in that
process? - correct answer ✔There is no change in kinetic energy, so there is
no work done on the bucket. The gravitational force is perpendicular to the
displacement.
A book is moving to the right across a table at constant speed. There are four
forces acting on it, its weight, W, which is straight down, the normal force of
the table, N, which is straight up, and two applied forces, one, called F1,
pointing 60º to the right of vertical and the other, F2, pointing 60º to the left of
vertical. List each of these forces in the order of increasing work, i.e. first list
the force which does the least work, then the second most, until you reach the
one that does the most work. Two forces that do equal work should have an
equal sign between them. Note that we are asking for the ranking to be done
by the amount of work, not by the magnitude of the amount of work. - correct
answer ✔F2 < W = N < F1
A ball is falling through the air. It has just two forces acting on it, its weight and
air resistance. Which of the following statements is true? - correct answer
✔There are both conservative and nonconservative forces acting on the ball.
All of the following statements are true except one. Which one is false? -
correct answer ✔a. Work done by a conservative force only depends on the
initial and final states.
b. One can never associate a potential energy function with a conservative
force.
c. An example of a nonconservative force is friction.
