1. A 525-N trunk is placed on an inclined plane that forms an angle of 30.0° with the horizontal.
What are the components of the weight parallel to the plane and normal to the plane?
2. A box rests on a plank that is inclined to the horizontal. As the angle between the plank and the
horizontal increases, does the component of the weight of the box parallel to the plank increase,
decrease, or remain the same? Explain your answer.
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3. An automobile weighing 12,000 N is parked on a 36° slope. Draw the free-body diagram showing
all of the forces acting on the automobile.
4. A 32-N force acts on a small mass in the positive x-direction. A 26-N force also acts on it in the
negative x-direction. What is the equilibrant of these two forces? You may want to draw a freebody diagram to help you solve the problem.
5. A child with a mass of 30.0 kg is moving down a slide at a playground. The angle the slide makes
with the ground is 60.0°, and the coefficient of friction between the child and the slide is 0.250.
What is the frictional force on the child? You may want to draw a free-body diagram to help you
solve the problem.
Chapter 5  Displacement and Force in Two Dimensions
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Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Section 2 Quiz
Teacher Support
All numerical answers have been rounded to the correct number of significant figures.
1. Fparallel  (525 N)(sin 30.0°)  262 N;
Fnormal  (525 N)(cos 30.0°)  455 N
2. increases: As the angle increases, the static friction component decreases.
3.
4. Fresultant  32 N  26 N  6 N; The equilibrant would have the same magnitude but in the opposite
of the resultant, Feq  6 N (in the negative x-direction)
5. Fnormal  (30.0 kg)(9.8 N/kg)cos 60.0°  147 N
Ffriction  Fnormal  (0.250)(147 N)  36.8 N
Chapter 5  Displacement and Force in Two Dimensions
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Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.