Physics — Algebra and Trigonometry · 35 minutes
Suggested grades 11–12 · Unit 1: Motion and Momentum · Lesson 1 of 2
Connect Net Force With a Velocity Change
Analyze supplied motion data and resolve a force into horizontal and vertical components.
Mr. S Teaches · Original starter lesson · HS-PHYS-01 · Grade range is planning guidance.Watch, notice, discuss
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Newton's Second Law | Forces & Motion | Physics | FuseSchool
By FuseSchool - Global Education
Practice F = ma and compare predicted acceleration with the finite velocity change in the lesson.
Open on YouTube: Newton's Second Law | Forces & Motion | Physics | FuseSchool (opens a new tab) ↗Newton's second law calculations | Physics | Khan Academy
By Khan Academy
Use a second algebra-based worked example; keep signs and units visible when evaluating the motion data.
Open on YouTube: Newton's second law calculations | Physics | Khan Academy (opens a new tab) ↗What idea from the video helps you calculate acceleration from a finite velocity change and test consistency with a net-force model? Identify one useful example and one limit of the video's model or explanation.
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Learning objective
Calculate acceleration from a finite velocity change and test consistency with a net-force model.
Before you begin
- Rearrange linear equations and use cosine of an angle.
Gather your materials
- Paper or notebook
- Pencil; calculator optional for numerical work; all task data supplied below
Language to know
- velocity
- Speed together with a direction.
- acceleration
- Velocity change divided by the elapsed time for this constant-acceleration model.
- component
- The part of a vector along a chosen direction.
Understand the concept
Technical report: A 3 kg cart changes from 1 m/s east to 5 m/s east in 2 s under a measured 6 N net eastward force. The level track and timing are controlled. For a separate idealized pull, a 10 N force at 30° above horizontal has horizontal component 10 cos30°; vertical forces must also be balanced or analyzed. Applied force is not automatically net force. This paper analysis assumes constant acceleration; it is not a physical pulling experiment.
Teach it step by step
- Read the report and assign east as the positive direction before writing quantities.
- Compute a = (5 − 1)/2 and compare ma with the reported net force.
- Sketch the angled pull and calculate its horizontal component using cos30°≈0.866.
- Use a precise text detail to explain why unmeasured friction or vertical imbalance could invalidate a simple horizontal prediction.
Make the thinking visible
Worked example or model response
The first acceleration is 2 m/s²; ma = 3×2 = 6 N, consistent with the report. The separate pull has horizontal component about 8.66 N, not 10 N. A component is not a second additional force to add to the original vector.
Guided practice
Together calculate a cart’s velocity change over 3 s if mass is 2 kg and net horizontal force is 4 N, starting at rest.
Independent practice
For a 2 kg cart under the idealized 10 N angled pull, with no other horizontal force, calculate horizontal acceleration. Explain which vertical assumption you would need on a level track.
Quick assessment
Can constant nonzero velocity by itself demonstrate a nonzero net force?
Answer key & assessment criteria
Answers and teaching guidance
- Guided: a=4/2=2 m/s²; the velocity change in 3 s is 6 m/s.
- Independent: Horizontal acceleration is 8.66/2≈4.33 m/s². A normal/support force and other vertical forces must produce the stated vertical condition; do not assume the angled force is wholly horizontal.
- Quick check: No. In the ideal constant-mass model, constant velocity corresponds to zero acceleration and zero net force.
Look for: Assess the stated objective using the concrete criteria and explanations in the answer key. Invite an alternative supported solution; distinguish a model’s prediction from an established observation.
Make it work for your learner
More support
Provide signed-quantity labels, a formula organizer and a right-triangle force sketch.
Extension challenge
Introduce a 2 N opposing horizontal friction force and recompute the net component and acceleration.
Verified references · Selected contributions
Standards connections
Selected NGSS high school-band contribution; full performance requires additional evidence and instruction.
Subject-content standards
These records identify the part of a subject standard practiced here. Course placement is instructional guidance; the source’s category or band remains authoritative.
Contributes to NGSS performance expectation
HS-PS2-1
NGSS · High school band
Analyze data connecting net force, mass and acceleration.
Read the official performance expectation ↗The lesson analyzes selected supplied data and a component model. It does not collect motion evidence or test variable forces and all sources of measurement uncertainty.
Verified 2026-11-04. Selected contribution, not full attainment.
Supporting literacy connections
These records apply to the specified reading, writing or communication task. They do not establish subject-content alignment.
Supporting Common Core literacy connection
RST.11-12.1
Common Core · Grades 11–12
Analyze technical details, distinctions and gaps using textual evidence.
Read the official standard ↗The activity explicitly analyzes the provided technical text, table or model. It contributes selected literacy practice rather than complete grade-band reading coverage or independent subject-content alignment.
Verified 2026-11-04. Selected contribution, not full attainment.