Lesson 9: Applying Newton's Laws of Motion
Overview:
Volleyball is a sport that involves teamwork and players knowing how to apply forces to the ball to redirect it. When the velocity of the ball is large, a player will usually "bump" the ball to slow it down so that another player can redirect it over the net.
At the instant the player bumps the ball, the ball exerts a large force on the player's arm, often causing soreness. Immediately after the interaction, the ball bounces upward. To explain the motion of each object during and after this interaction requires an understanding of Newton's Laws.
At the instant the player bumps the ball, the ball exerts a large force on the player's arm, often causing soreness. Immediately after the interaction, the ball bounces upward. To explain the motion of each object during and after this interaction requires an understanding of Newton's Laws.
Curriculum Expectations:
Overall Expectations:
B2. Investigate, in qualitative and quantitative terms, forces involved in uniform circular motion and
motion in a plane, and solve related problems.
B3. Demonstrate an understanding of the forces involved in uniform circular motion and motion in a plane.
Specific Expectations:
B2.1 Use appropriate terminology related to dynamics, including, but not limited to: inertial and non-inertial frames of reference, components, centripetal, period, frequency, static friction, and kinetic friction.
B2.2 Solve problems related to motion, including projectile and relative motion, by adding and subtracting two-dimensional vector quantities, using vector diagrams, vector components, and algebraic methods.
B2.3 Analyse, in qualitative and quantitative terms, the relationships between the force of gravity, normal force, applied force, force of friction, coefficient of static friction, and coefficient of kinetic friction, and solve related two-dimensional problems using free-body diagrams, vector components, and algebraic equations (e.g., calculate the acceleration of a block sliding along an inclined plane or the force acting on a vehicle navigating a curve).
B2.4 Predict, in qualitative and quantitative terms, the forces acting on systems of objects (e.g., masses in a vertical pulley system [a “dumb waiter”], a block sliding off an accelerating vehicle, masses in an inclined-plane pulley system), and plan and conduct an inquiry to test their predictions.
B2.5 Analyse, in qualitative and quantitative terms, the relationships between the motion of a system and the forces involved (e.g., a block and algebraic equations to solve related problems sliding on an inclined plane, acceleration of a pulley system), and use free-body diagrams and algebraic equations to solve related problems.
B2. Investigate, in qualitative and quantitative terms, forces involved in uniform circular motion and
motion in a plane, and solve related problems.
B3. Demonstrate an understanding of the forces involved in uniform circular motion and motion in a plane.
Specific Expectations:
B2.1 Use appropriate terminology related to dynamics, including, but not limited to: inertial and non-inertial frames of reference, components, centripetal, period, frequency, static friction, and kinetic friction.
B2.2 Solve problems related to motion, including projectile and relative motion, by adding and subtracting two-dimensional vector quantities, using vector diagrams, vector components, and algebraic methods.
B2.3 Analyse, in qualitative and quantitative terms, the relationships between the force of gravity, normal force, applied force, force of friction, coefficient of static friction, and coefficient of kinetic friction, and solve related two-dimensional problems using free-body diagrams, vector components, and algebraic equations (e.g., calculate the acceleration of a block sliding along an inclined plane or the force acting on a vehicle navigating a curve).
B2.4 Predict, in qualitative and quantitative terms, the forces acting on systems of objects (e.g., masses in a vertical pulley system [a “dumb waiter”], a block sliding off an accelerating vehicle, masses in an inclined-plane pulley system), and plan and conduct an inquiry to test their predictions.
B2.5 Analyse, in qualitative and quantitative terms, the relationships between the motion of a system and the forces involved (e.g., a block and algebraic equations to solve related problems sliding on an inclined plane, acceleration of a pulley system), and use free-body diagrams and algebraic equations to solve related problems.
Success Criteria:
- What does it mean for an object to be in a state of equilibrium?
- Can an object that is moving be in equilibrium? Explain.
- Compare the process of solving problems for objects in equilibrium vs. accelerating objects.
Time Allocation: 2 hours
Learning Activities:
Read pages 77 - 82 from Nelson 2.3
In the playlist below, video:
- Will show you how calculate the 2 tensions of a rope (attached to the ceiling at 45 degree and wall) with a hanging mass.
- Will show you how to calculate the acceleration of 2 masses around a pulley attached to a table.
- Will cover Newton's Second Law of Physics: F=ma. Without Pulley.
- will cover Newton's Second Law of Physics: F=ma. With Pulley.
Practice question 3 on page 79.
Practice questions 2, 3, and 4 on page 82.
Practice questions 2, 3, and 4 on page 82.
Task:
Solve questions 1, 3, 4, and 5 from Nelson 2.3 Review on page 83.
Optional Extension:
Optional Extension:
- Practice questions 5 and 6 on page 82.
Reflect:
At the instant that both the ball and the player's arms are in contact, the action force is the upward force that the plalyer exerts on the ball. The reaction force is the downward force that the ball exerts on the player's arms. During the collision, the ball accelerates upward and the player's arms accelerate downward. Can you think of other examples in sports where you can apply Newton's Laws to analyze the motion? Is it possible to have an action force without a reaction force? If the action force is equal in magnitude to the reaction force, how can there ever be an acceleration?
Additional Resources:
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This video will show you how to calculate the acceleration and tensions of 2 objects around a pulley sliding on a wedge.
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This video will show you how to calculate the force of a system 2 masses around a pulley attached to a cart.
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