Resultant Forces

Question 1

A sled is being pulled to the east with a force of 6 N and a wind pushes it to the west with a force of 2 N. What is the magnitude and direction of the resultant force on the sled?

Accepted Answer

4 N east

Answer

8 N west

Answer

4 N west

Answer

8 N east

Question 2

A sled is being pulled eastward with a force of 8 N and a wind pushes it westward with a force of 3 N. What is the magnitude and direction of the resultant force acting on the sled?

Accepted Answer

5 N eastward

Answer

11 N westward

Answer

5 N westward

Answer

11 N eastward

Question 3

A 2 kg textbook rests on a horizontal desk. A student pulls the textbook with a rope that applies a 6 N force to the right. The desk’s surface is rough enough that a friction force of 6 N acts on the book to the left. Which set of forces should be shown in a correct free‑body diagram for the book, and what does it tell you about the book’s motion?

Accepted Answer

Four forces: weight 20 N downward, normal 20 N upward, tension 6 N to the right, friction 6 N to the left; the forces balance so the book stays still.

Answer

Three forces: weight 20 N downward, normal 20 N upward, tension 6 N to the right; the forces are unbalanced, so the book would move right.

Answer

Four forces: weight 20 N downward, normal 14 N upward, tension 6 N to the right, friction 6 N to the left; the net upward force would lift the book.

Answer

Two forces: weight 20 N downward and normal 20 N upward; the rope force is ignored because it is internal.

Try three questions

A sled is being pulled to the east with a force of 6 N and a wind pushes it to the west with a force of 2 N. What is the magnitude and direction of the resultant force on the sled?

A sled is being pulled eastward with a force of 8 N and a wind pushes it westward with a force of 3 N. What is the magnitude and direction of the resultant force acting on the sled?

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