Texas TEKS 8.7

8.7 is a TEKS knowledge and skills statement. These are the student expectations under it.

• 8.7.A

  calculate and analyze how the acceleration of an object is dependent upon the net force acting on the object and the mass of the object using Newton's Second La...

• 8.7.B

  investigate and describe how Newton's three laws of motion act simultaneously within systems such as in vehicle restraints, sports activities, amusement park ri...

01

What Students Need to Do

Students calculate net force and use a = Fnet ÷ m to find acceleration. They explain how force and mass affect acceleration, then identify all three Newton’s laws operating in one system.

02

What Mastery Looks Like

Students combine forces with correct directions, calculate acceleration with units, and predict changes when force or mass changes. They can analyze a seatbelt, sport, ride, tectonic event, or rocket and explain each law with evidence.

03

Common Misconceptions

Students may add all forces without considering direction, or think an object needs a net force to keep moving. They may think greater mass always means greater acceleration. They may also think action-reaction forces cancel, even though they act on different objects.

04

How to Assess It

Give this exit ticket: “A 4 kg cart has 18 N right and 6 N left. Find its acceleration, then explain all three laws during a sudden stop.”

1. 01

   Push empty and loaded carts with the same spring scale force, measure acceleration, and graph acceleration against mass.

2. 02

   Write how all three laws act when a soccer player kicks a ball, naming the objects in each action-reaction pair.

3. 03

   Play a net-force card sort, matching force diagrams, masses, calculated accelerations, and motion predictions.

4. 04

   Analyze a seatbelt and airbag diagram, then explain how each reduces injury using force, mass, acceleration, and inertia.

• 6.7

  Force, motion, and energy. The student knows the nature of forces and their role in systems that experience stability or change. The student is expected to:

• 1.7

  Force, motion, and energy. The student knows that forces cause changes in motion and position in everyday life. The student is expected to:

• 3.7

  Force, motion, and energy. The student knows the nature of forces and the patterns of their interactions. The student is expected to:

• 5.7

  Force, motion, and energy. The student knows the nature of forces and the patterns of their interactions. The student is expected to: