Find the gravitational force exerted by the earth on a rock of mass 100kg which lies on the surface of the earth. Mass of earth is 6*10^24 kg, radius if the earth is 6.4*10^6 mand G= 6.67*10^-11 SI units.

Taylor's experiment: 1. accurately measured the speed of light 2. locked together the phases of two light sources so that the interference pattern would not shift 3. showed that man's reaction time was much slower than the speed of light 4. showed that individual photons have wave characteristics

An athlete swings a ball, connected to the end of a chain, in a horizontal circle. the athlete is able to rotate the ball at the rate of 8.13 rev/s when the length of the chain is 0.600 m. when he increases the length to 0.900 m, he is able to rotate the ball only 6.04 rev/s. (a) which rate of rotation gives the greater speed for the ball? 6.04 rev/s 8.13 rev/s (b) what is the centripetal acceleration of the ball at 8.13 rev/s? m/s2 (c) what is the centripetal acceleration at 6.04 rev/s? m/s2

2. circled insects have mutations, or changes to their dna. how many of the offspring insects in this generation have mutations?