Technical Science - Term 1 - Week 6

Newton's first law states that an object at rest will remain at rest, and an object in motion will remain in motion at a constant velocity unless acted upon by a net external force. This principle emphasizes the concept of inertia. The second law introduces the relationship between force, mass, and acceleration, expressed as F = ma, indicating that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. Finally, the third law states that for every action, there is an equal and opposite reaction, highlighting the interactions between objects.

Consider a scenario where two forces are acting on a box: a 10 N force to the right and a 5 N force to the left. To find the net force, we subtract the opposing forces: Net Force = 10 N (right) - 5 N (left) = 5 N to the right. This example illustrates how to determine the overall effect of multiple forces acting on an object.

In pairs, students will observe a scenario in the classroom, such as a book resting on a table. They will identify the forces acting on the book, including gravitational force pulling it down and the normal force from the table pushing it up. Students will discuss how these forces balance each other and keep the book at rest, reinforcing the concept of equilibrium.

Students will complete a worksheet with various problems involving forces and motion. They will calculate the net force in different scenarios, such as a car accelerating with a force of 200 N and a frictional force of 50 N opposing it. They will also provide examples of everyday situations that illustrate Newton's laws, encouraging them to apply theoretical knowledge to practical contexts.

• The relationship between force and mass.
• The tendency of objects to resist changes in motion.
• The action-reaction principle.

Answer: The tendency of objects to resist changes in motion.

Newton's first law, also known as the law of inertia, states that an object will not change its state of motion unless acted upon by a net external force.

• F = m + a
• F = ma
• F = m/a

Answer: F = ma

Newton's second law states that the force acting on an object is equal to the mass of the object multiplied by its acceleration.

Answer: A swimmer pushes water backwards, and the water pushes the swimmer forward.

This example illustrates the action-reaction principle, where the action of pushing water results in the reaction of moving forward.

• 5 m/s²
• 20 m/s²
• 2 m/s²

Answer: 5 m/s²

Using F = ma, acceleration can be calculated as a = F/m = 10 N / 2 kg = 5 m/s².

Answer: Inertia is the tendency of an object to resist changes in its state of motion.

Inertia is directly related to mass; the greater the mass, the greater the inertia.

• A car accelerating.
• A book resting on a table.
• A ball rolling down a hill.

Answer: A book resting on a table.

Balanced forces occur when the net force is zero, as in the case of a book at rest on a table.

• It will stop.
• It will accelerate.
• It will continue moving at a constant velocity.