20. Which of the following is true? 1. Friction slows down a moving object II. Smooth surface has more friction Objects move slowly on a rough surface IV. Friction is not present in a smooth surface A. 1,11 B. 11,111 C. 1,111 D. I,III;IV 21. The boat is sailing on the sea slows down. What kind of friction is acting on it? A. Static friction B. Rolling friction C. Fluid friction D. Sliding friction 22. Why does a car travel faster on a road going down than in going up? A. It is moving against gravity. C. It is moving toward gravity. B. It is being pushed by the wind D. It is being pulled by the weig 23. Where would an object with the weight of 1-kg be the heaviest? A. In space B. on Earth C. on the moon D. between the Moon and Eart! 24. If the moon is closer to the Earth, what would happen to the force between them? A. disappear B. get bigger C. get smaller D. stay the sar 25. Which of these have the biggest gravitational pull on Earth? A. a 10-kg rice B. a 100 kg boxer C. a 100 g mouse D. a 1000 kg elephant
