Tham khảo tài liệu 'sat ii physics (sn) episode 1 part 8', ngoại ngữ, ngữ pháp tiếng anh phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Every 76 years Halley s comet passes quite close by the Earth. At the most distant point in its orbit it is much farther from the sun even than Pluto. Is the comet moving faster when it is closer to Earth or closer to Pluto According to Kepler s Second Law objects that are closer to the sun orbit faster than objects that are far away. Therefore Halley s comet must be traveling much faster when it is near the Earth than when it is off near Pluto. Key Formulas 176 Practice Questions Questions 1-3 refer to a ball of mass m circular motion with instantaneous velocity on a string of length R swinging around v and centripetal acceleration a. in 1. What is the centripetal acceleration of the A a 4 B a 2 C a D 2a E 4a ball if the length of the string is doubled 2. What is the centripetal acceleration of the ball if the instantaneous velocity of the ball is doubled A a 4 B a 2 C a D 2a E 4a 3. What is the centripetal acceleration of the ball if its mass is doubled A a 4 B a 2 C a D 2a E 4a 4. . A bullet of mass m traveling at velocity v strikes a block of mass 2m that is attached to a rod length R. The bullet collides with the block at a right angle and gets stuck in the block. The rod free to rotate. What is the centripetal acceleration of the block after the collision A v2 R B 1 2 v2 R C 1 3 v2 R D 1 4 v2 R E 1 9 v2 R of is 177 5. . A car wheel drives over a pebble which then sticks to the wheel momentarily as the wheel displaces it. What is the direction of the initial acceleration of the pebble A B C D E 6. . If we consider the gravitational force F between two objects of masses and respectively separated by a distance R and we double the distance between them what is the new magnitude of the gravitational force between them A F 4 B F 2 C F D 2F E 4F 7. . If the Earth were compressed in such a way that its mass remained the same but the distance around the equator were just one-half what it is now what would be the acceleration due to gravity at the surface of the Earth
