OzoCop

Aim: studying uniform motion and proportionality. Middle school 2^nd class students could solve the problem using proportions and their properties, while 3^rd class students could use functions and their cartesian representation

Material:

Two OZOBOTs

Black felt tip pen or

Card with Path an example is provided

A thief robbed a jewelry store. He goes out and runs at the speed of TT km / h. A policeman sees him and starts chasing him. When the chase begins, the policeman is away from the thief d m. The policeman runs at PP km / h. Will he be able to reach the thief within z km of the jewelry store?

This is a typical exercise can be found in a physics book: it can be solved at different levels, depending on the age of the students. Also middle school students can solve it reflecting on the proportionality between the speed of a train, XX, and its distance from the starting point, x, and so solving a proportion like the following:

a:AA=b:BB

with a-b=d

Otherwise, if functions and their cartesian representation have been already introduced, a graphical solution can be given.

In any case, this activity will help them to visualize the result.

Procedure:

• STEP 1

Write a code for following a line at a defined speed.

Set a velocity and upload the code on one OZOBOT.

Measure the time OZOBOT takes to cover a fixed distance, and calculate the actual speed.

Repeat the same procedure on the other OZOBOT.

• STEP 2

Calculate the point where the two chasing OZOBOT will reach the chased one.

• STEP 3

Run the two OZOBOTs simultaneously, each from its starting point. Does the policeman reach the thief according to your prediction?

Extensions:

• Calculate and check the time before crossing.

• Make the chasing OZOBOT’s led flashing as a police car