Massachusetts Comprehensive Assessment System

2019, High School Intro Physics

Question 23: Open-Response

Reporting Category: Motion and Forces
Standard: 1.4 - Interpret and apply Newton's three laws of motion.
Standard: Sci.HS.PHY.2.01 - Analyze data to support the claim that Newton’s second law of motion is a mathematical model describing change in motion (the acceleration) of objects when acted on by a net force. Clarification Statements: Examples of data could include tables or graphs of position or velocity as a function of time for objects subject to a net unbalanced force, such as a falling object, an object rolling down a ramp, and a moving object being pulled by a constant force. Forces can include contact forces, including friction, and forces acting at a distance, such as gravity and magnetic forces. State Assessment Boundary: Variable forces are not expected in state assessment.

A moving walkway is like a sidewalk that moves at a constant speed. It is used to transport people from one location to another within a large building, such as an airport. The diagram shows a moving walkway.

The table shows data about two people on the same moving walkway. Person 1 steps onto the walkway from rest and stands on it. Person 2 steps onto the walkway while already walking and continues to walk.

Person	Mass (kg)	Distance Moved on Walkway (m)	Time on Walkway (s)
1	88	120	240
2	52	120	70

a. Using the data for person 1, calculate the speed of the walkway. Show your calculations and include units in your answer.

Stepping onto the walkway, person 1 accelerates from an initial speed of 0 m/s to the speed of the walkway in 0.6 s.

b. Calculate the acceleration of person 1. Show your calculations and include units in your answer.

c. Calculate the net force that accelerated person 1. Show your calculations and include units in your answer.

Person 1 and person 2 have the same acceleration as they step onto the moving walkway.

d. Identify whether the net force acting on person 1 is greater than, less than, or equal to the net force acting on person 2. Explain your answer.

Scoring Guide for Idea Development

Select a score point in the table below to view the sample student response.

Score	Description
4	The response demonstrates a thorough understanding of how to solve problems involving speed and acceleration and apply Newton's second law of motion. The response correctly calculates the speed of the walkway, the acceleration of person 1, and the force that accelerated person 1. The response correctly compares the net force acting on person 1 and person 2 and clearly explains the answer.
4
3	The response demonstrates a general understanding of how to solve problems involving speed and acceleration and apply Newton's second law of motion.
2	The response demonstrates a limited understanding of how to solve problems involving speed and acceleration and apply Newton's second law of motion.
1	The response demonstrates a minimal understanding of how to solve problems involving speed and acceleration and apply Newton's second law of motion.
0	The response is incorrect or contains some correct work that is irrelevant to the skill or concept being measured.

Note: There are 2 sample student responses for Score Point 4.

High School Intro Physics

Question 12: Waves and Radiation

Question 23: Motion and Forces

Question 32: Motion and Forces

Question 44: Heat and Heat Transfer

Question 45: Electromagnetism

Return to the MCAS 2019 Student Work Directory

Last Updated: May 5, 2020