Learning Task 6: Study the following situations and answer the question for each Remember what you have learned about gravity and friction. Write your explanations on your answer sheet.

1 Place a book on top of a table. What keeps the book from falling? How is this possible?

2. Roll a marble on top of a level surface. Make it stop. Slide a light book on top of the same level surface by giving it an initial push. Did the book continue to slide? What is responsible for making the sliding book slow down and eventually stop?

3. Drop a small stone and a piece of paper from the same height at the same time. Observe closely the motion of the stone and the paper as they fall. Which of them reached the ground first? Why did not the other one reach the ground at the same time as the first?

4. What is the importance of friction in our daily life?

5 Why do we need gravity?

1. For example, when a book is placed on a table, the normal force keeps the book from falling through the table. Gravity is pulling the book downward, but since the book isn't actually falling, something must be pushing it up. This force is called the normal force

2.the sliding of the book cannot continue because the friction will slow down the sliding book to stop completely

3. Stone

4.Friction can slow things down and stop stationary things from moving. In a frictionless world, more objects would be sliding about, clothes and shoes would be difficult to keep on and it would be very difficult for people or cars to get moving or change direction

5.Gravity is very important to us. We could not live on Earth without it. The sun's gravity keeps Earth in orbit around it, keeping us at a comfortable distance to enjoy the sun's light and warmth. It holds down our atmosphere and the air we need to breathe.