Objective: To identify whether positive, negative, or zero work is being done, to identify the force that is doing the work, and to describe the energy transformation associated with such work.
You are NOT using this Activity as a Logged-in student. You may log in and return to this page. Or you can do this Activity as a Guest. If you continue as a Guest, a record of completing it will NOT be stored in our database.
This is the Teacher Preview mode of this Science Reasoning task.
Teacher Preview allows teachers to preview the Questions for each Activity and their organization into Question Groups. This allows you to evaluate the appropriateness of the Activity for your students. Teacher Preview also allows you to consider whether you would like to customize the task by removing one or more of the Activities from the assignment. Customization can be done within Task Tracker when you assign the task to your class.
You are currently logged in with the username shown below. As long as you maintain an internet connection, any of the parts of this Activity that you complete will be saved in your account.
Tap on the Start Button to begin.
Start Teacher Preview Mode
Use Key Pad to Enter Name. Then Tap the Enter Button.
Analyze the design of three related friction experiments.
Use provided data and the resulting model to make predictions regarding the amount of static or kinetic friction.
An Investigation of Friction Between Two Surfaces
Use the data from three friction experiments to develop a model regarding the variables that affect friction.
A Model for Friction
No, Stay Here
Each Science Reasoning task is based on a passage or story that presents data and information or describes an experiment or phenomenon. Students must combine an understanding of science content and science reasoning skills (science practices) to answer questions about the passage or story.
Tap anywhere to view the passage.
Currently Displaying ...
Some Interactivity and Check Answer functionality is disabled when in Teacher Preview mode.
Tap to View Information:
This is the last Activity
in this task.
Friction is a force that resists the motion of objects. A group of students are conducting experiments on friction.
Figure 1 depicts a procedure that is used to measure the friction force. A horizontal force is applied to a block on a table to accelerate it from rest. One observes that the force needed to initiate the motion (accelerate it from rest) is greater than the force needed to sustain the motion at a constant speed. Masses can be added to the block, thus increasing the load (L). The force required to initiate the motion is equal to the maximum value of the static friction force (Fstatic). The force required to sustain the motion at a constant speed is equal to the kinetic friction force (Fkinetic). Table 1 represents typical data from such an experiment.
A student decides to investigate the effect of the surface on the amount of friction. She layers the bottom of the block with coarse sandpaper and then repeats the procedure described in Experiment 1. Her data are shown in Table 2.
Another student makes an effort to determine if the area of contact between the block and the table affects the amount of friction. The student finds a rectangular block with three unequal length sides. The three areas of the sides of the block are shown. The student pulls the block (without the sandpaper) along each of the sides at a constant speed. The data are shown in Table 3.
This is the last QG
of the last Activity.
Learn More About Task Tracker and Teacher Preview.
This is the last Question
of the last Activity.
Scroll to View Whole Passage. Tap to Close.
If you return to the Main Menu, then you will lose all your progress
on this activity.
Are you sure you want to return to the Main Menu?
Template Version 1.2 Added Question Scene 4 for Table Completion
Experimental Design,A Model for Friction,Making Predictions
One aspect of safe driving involves the ability to stop a car readily. This ability depends upon the driver's alertness and readiness to stop, the conditions of the road, the speed of the car, and the braking characteristics of the car. The actual distance it takes to stop a car consists of two parts - the reaction distance and braking distance.
When a driver sees an event in his/her field of view that might warrant braking (for example, a dog running into the street), a collection of actions must be taken before the braking actually begins. First the driver must identify the event and decide if braking is necessary. Then the driver must lift his/her foot off the gas pedal and move it to the brake pedal. And finally, the driver must press the brake down its full distance in order to obtain maximum braking acceleration. The time to do all this is known as the reaction time. The distance traveled during this time is known as the reaction distance. Once the brakes are applied, the car begins to slow to a stop. The distance traveled by the car during this time is known as the braking distance. The braking distance is dependent upon the original speed of the car, the road conditions, and characteristics of the car such as its profile area, mass and tire conditions. Figure 1 shows the stopping distance for a Toyota Prius on dry pavement resulting from a 0.75-second reaction time.
The reaction time of the driver is highly dependent upon the alertness of the driver. Small changes in reaction time can have a large effect upon the total stopping distance. Table 1 shows the reaction distance, braking distance, and total stopping distance for a Toyota Prius with an original speed of 50.0 mi/hr and varying reaction times.