Friction

LA FISICA SPERIMENTA… L’INGLESE

FRICTION

When moving objects come in contact with one another, they resist each other’s motion. No surface is completely smooth. The resistance that is caused by the rubbing together of these uneven surfaces is known as friction. All motion is retarded by friction.

EXPERIMENT

Take a book, connect it with the spring balance on a table and record the force required to move it.

Put another identical book on the first one and repeat the previous action recording the new value of the required force.

Note down that the force is doubled, so the friction depends on the weight of the object moved.

GLOSSARY

smooth – liscia, levigata, piana surface – superficie by the rubbing – dallo strofinare Uneven – irregolari spring balance – dinamometro record – registrare

Doubled – raddoppiata weight – peso

ACTIVITIES

1. Match the word to its translation.

To connect movimento To contact evidenziare Motion collegare Object contattare To point out oggetto

2. Answer the following questions:

a) What happens when moving objects come in contact with one another?

b) Why?

c) How is the resistance caused by the rubbing together of these uneven surfaces known?

3. Multiple choice:

a) Connect a book to a ……….

(1) spring balance (2) spring flower (3) balance (4) compass b) Put a ………..on the first book.

(1) book (2) balance (3) copybook (4) hand

c) Friction depends on the……….of the object moved.

(1) weight (2) colour (3) dimension (4) height