Một vật có khối lượng 75g được ném lên từ độ cao 1,1m so với mặt đất với tốc độ 12m/s. Khi nó đạt độ cao2,1m thì tốc độ của nó là 10,5m/s. a/ Tính công đã thực hiện trên vật bởi trọng lượng của nó?b/ Cơ năng của vật bị tiêu tán bởi lực cản của không khí?

Aball is thrown upward. at a height of 10 meters above the ground, the ball has a potential energy of 50 joules (with the potential energy equal to zero at ground level) and is moving upward with a kinetic energy of 50 joules. what is the maximum height h reached by the ball? consider air friction to be negligible. 1. h ≈ 10 m 2. h ≈ 50 m 3. h ≈ 30 m 4. h ≈ 40 m 5. h ≈ 20 m 003 10.0 points which of the two object shown below has the greatest kinetic energy? a m b 1 2 m v 2v 1. kinetic energies are the same. 2. a 3. b 4. unable to determine. 004 10.0 points tim, with mass 74.6 kg, climbs a gymnasium rope a distance of 3.1 m. the acceleration of gravity is 9.8 m/s 2 . how much potential energy does tim gain? answer in units of j. 005 10.0 points a car is moving at 64 miles per hour. the kinetic energy of that car is 5 × 105 j. how much energy does the same car have when it moves at 111 miles per hour? answer in units of j. 006 10.0 points an 102 kg man climbs up a 1 m high flight of stairs. the acceleration of gravity is 9.81 m/s 2 . w

2. which of the following does not affect the electrical resistance of a body? a. material composing the body b. bodies directly surrounding the body c. length of the body > d. temperature of the body

Stephanie lives in california, and her cousin thomas lives in france. which coordinate system would be most useful if the two wanted to observe the same meteor shower and discuss their observations over online chat as they're making them? a. horizontal b. equatorial c. azimuth-altitude d. celestial or azimuth-altitude