You and your bicycle have combined mass 80.0 kg. When you reach the base of a bridge, you are traveling along the road at 5.00 m>s (Fig. P6.74). At the top of the bridge, you have climbed a vertical distance of 5.20 m and slowed to 1.50 m>s. Ignore work done by friction and any inefficiency in the bike or your legs. (a) What is the total work done on you and your bicycle when you go from the base to the top of the bridge? (b) How much work have you done with the force you apply to the pedals?
ASTRO Lesson 6 – the moon Lecture 31, 32 ▯ ▯ Escape speed of the moon is about 1/6 of the earth For earth = 11.2 km/s For moon = 2.4 km/s ▯ ▯ Earth doesn’t rotate around sun, center of mass of the earth-moon system rotates around the sun ▯ ▯ Sister theory Moon and earth formed at about the same time, with the same stuff and became the way they are now Chemical compositions of dirt on the moon and earth are pretty similar - surfaces Density of the moon is way less than the density of the earth Not great ▯ Daughter theory When earth first formed, it was a giant molten ball of stuff (spinning fast). A chunk of the earth smashed off and created the moon
