Both objects feel it

The idea

Whenever two objects interact, each object experiences a force from the other, and both stop experiencing it as soon as the interaction ceases.

Feel your hand

You push a table with your hand. You may feel something on your hand too.

Is there a force on your hand?

• Yes, from the table
• No
• Only when the table moves

Push and stop

Press Push, then Stop pushing. Watch both arrows.

Two forces

Both the hand and the table felt a force, one from the other. When the pushing stopped, both forces disappeared.

Whenever two objects interact, each object experiences a force from the other. As soon as the interaction ceases, the two objects no longer experience the force.

Notes

When two objects interact, each feels a force from the other. As soon as the interaction ceases, both forces are gone.

Check yourself

When two objects interact, each object experiences …

A hand pushes a table. Which of them feels a force?

The hand stops pushing the table. What happens to the forces?

When are two objects experiencing forces from each other?

• no force. Both objects experience a force.
• a force from the other — correct. Yes!
• a force only if it is heavier. Weight does not matter. Each experiences a force from the other.
• Only the table. The hand feels a force from the table too.
• Only the hand. The table feels a force from the hand too.
• Both the hand and the table — correct. Yes!
• Both disappear — correct. Yes!
• They stay for a minute. As soon as the interaction ceases, the forces are gone.
• Only the force on the table disappears. Both objects stop experiencing the force.
• Always, even when far away from each other. The forces are there while they interact. They stop when the interaction ceases.
• While they interact — correct. Yes!
• Only after they separate. After they separate, the interaction has ceased and the force is gone.