Identifying Forces
A student pushes a box across the classroom floor. What type of force is the student applying?
What is an applied force?
Two students push a box with 10 N to the left and 10 N to the right. Are the forces balanced or unbalanced?
What are balanced forces?
A box has 8 N pushing right and 3 N pushing left. What is the net force?
Newton’s Third Law states that for every action force, there is this type of reaction force.
A student pushes a classroom wall with both hands. Identify the two objects interacting and describe the force each object exerts.
Student pushes wall; wall pushes student in the opposite direction with equal force.
A book rests on a table. What force pulls the book toward Earth?
What is gravity?
A box has 15 N of force pushing right and 5 N pushing left. Are the forces balanced or unbalanced?
What are unbalanced forces?
A cart has 12 N pushing left and 12 N pushing right. What is the net force?
What is 0N?
A student pushes against a wall. What force does the wall exert in response?
What is the wall pushing the student with an equal force in the opposite direction?
A swimmer pushes water backward while swimming forward. Identify the action force and the reaction force.
Swimmer pushes water backward; water pushes swimmer forward.
A soccer ball slows down as it rolls across grass. What force opposes the ball’s motion?
What is Friction?
An object has a net force of 0 N. What does this tell you about the forces acting on the object?
A box has 20 N pushing right, 5 N pushing left, and another 5 N pushing left. What is the net force?
A student pushes a wall with a force of 50 N to the right.
Identify the force the wall exerts on the student, including its magnitude and direction.
What is 50 N to the left?
A book rests on a table. Identify the Newton's Third Law force pair involving the book and Earth.
Earth pulls book downward; book pulls Earth upward through gravity.
A magnet attracts a paper clip without touching it. What type of force is acting?
What is a magnetic force?
A toy car moves in a straight line at a constant speed. What can you conclude about the net force acting on it?
What is a net force is 0N?
A student draws a force diagram showing:
24 N to the right
9 N to the left
6 N to the left
The student reports a net force of 39 N to the right.
Identify the student's error, calculate the correct net force, and explain the correct process.
The student added opposing forces. Correct calculation: 24-(9+6)=9N right.
A skateboarder pushes backward against the ground with one foot. Identify the two objects interacting and describe the action-reaction force pair.
What is the skateboarder pushing the ground backward and the ground pushing the skateboarder forward with an equal and opposite force?
Two ice skaters push against each other and move apart. Identify the two forces in this interaction and explain how they are related.
Each skater pushes the other; each experiences an equal and opposite force.
A box rests on the floor. Identify two forces. (Up and down)
What are Gravity downward and Normal force upwards?
Two students pull a rope in opposite directions. One pulls with 45 N, and the other pulls with 45 N.
Determine the net force and explain whether the forces are balanced or unbalanced.
15 N right; unbalanced.
A cart has a net force of 18 N to the left. Three forces act on it:
30 N to the right
12 N to the left
One unknown force
Determine the magnitude and direction of the unknown force. Show your calculations.
36 N left. The leftward forces total 30 N plus the unknown force, while 30 N acts right. To get 18 N left, the unknown force must be 18 N left.
A swimmer pushes water backward while swimming forward.
Identify the two interacting objects and describe the action-reaction force pair.
Swimmer pushes water backward; water pushes swimmer forward with equal magnitude and opposite direction.
A soccer player kicks a ball. The ball moves forward, and the player's foot experiences a force in the opposite direction. Identify the interacting objects and explain the action-reaction pair.
Foot pushes ball forward; ball pushes foot backward.