This is a map showing the approximate positions of the continents millions of years ago, after the breakup of the last supercontinent. Assume that South America and Africa diverged (separated) at an average rate of 3.5 cm/year (centimeters per year). If the two land masses are now 2850 km (kilometers) apart, how many years ago did they separate? A. 1.2 • 10^8 years

B. 1.0 • 10^5 years

C. 1.2 • 10^7 years

D. 8.1 • 10^7 years

E. 8.14 • 10^5 years

F. 1.05 • 10^4 years

If the speed of a particle triples ,by what factor does its kinetic energy increase?

1point) a skydiver weighing 130 lb (including equipment) falls vertically downward from an altitude of 14,000 ft and opens the parachute after 20 s of free fall. assume that the force of air resistance, which is directed opposite to the velocity, is of magnitude 0.85|v|0.85|v| when the parachute is closed and is of magnitude 17|v|17|v| when the parachute is open, where the velocity vv is measured in ft/s. assume that acceleration due to gravity has magnitude 32 ft/s/s; remember that weight is the product of mass and gravitational acceleration. find the speed of the skydiver when the parachute opens. speed is 150.6121788 ft/s find the skydiver's height when the parachute opens. height is 2338.98591 ft find the limiting velocity vlvl after the parachute opens. (think about whether this should be positive or negative.) vl=vl= 7.647 ft/s

When you jump from an elevated position you usually bend your knees upon reaching the ground. by doing this, you make the time of the impact about 10 times as great as for a stiff-legged landing. in this way the average force your body experiences is a) less than 1/10 as great. b) more than 1/10 as great. c) about 1/10 as great.d) about 10 times as great.