Quiz Chapter 8: Force and Motion

1. A balanced seesaw has a 300 N child sitting 2.0 m to the left of the pivot. How far from the pivot must a 400 N child sit on the right side to maintain balance?

1. 1.5 m
2. 2.6 m
3. 1.0 m
4. 3.0 m

2. Why does liquid pressure increase as a diver descends deeper into the ocean?

1. Water temperature increases with depth
2. The weight of the liquid column above the diver increases with depth
3. Water density decreases at greater depth
4. Atmospheric pressure disappears underwater

3. A force of 50 N is applied perpendicular to a door at a distance of 0.8 m from the hinges (pivot). What is the turning moment of the force?

1. 40 N m
2. 62.5 N m
3. 50.8 N m
4. 20 N m

4. Why does a suction cup stick firmly to a smooth glass window when pressed flat against it?

1. Air inside cup expands and pulls the cup
2. Air is squeezed out, creating a low pressure zone inside; higher external atmospheric pressure holds it in place
3. Static electricity glues the rubber to glass
4. Glass exerts high normal force pushing it inward

5. Which set of items belongs to First Class Levers (Pivot located between Load and Effort)?

1. Wheelbarrow and bottle opener
2. Scissors and crowbar
3. Tweezers and fishing rod
4. Ice tongs and broom

6. Which type of force always acts directly opposite to the direction of motion between two moving touching surfaces?

1. Gravitational force
2. Frictional force
3. Normal force
4. Buoyant force

7. Why do high-heeled shoes sink more deeply into soft mud compared to flat-soled sneakers worn by a person of the same weight?

1. High heels exert less total force on the ground
2. High heels have a smaller contact surface area, creating higher pressure
3. Flat sneakers create higher pressure on the ground
4. High heels increase gravitational pull

8. An object floats in water when the upward buoyant force is equal to what quantity?

1. Atmospheric pressure
2. Weight of the object (gravitational force)
3. Frictional force of water
4. Surface area of the object

9. Which action will increase the moment of force when loosening a tight nut using a wrench?

1. Applying force closer to the pivot
2. Using a wrench with a longer handle and applying force at the far end
3. Applying a smaller force perpendicular to the handle
4. Greasing the nut to reduce handle length

10. What effect does force exhibit when a sculptor shapes clay with their hands?

1. Changes object's direction
2. Changes object's speed
3. Changes object's shape and size
4. Stops a moving object