Which of the following would have the highest power rating? 100 joules of energy used in 0.5 seconds 500 joules of energy used in 0.5 seconds 100 joules of energy used in 0.25 seconds 500 joules of energy used in 0.25 seconds

If a rock is thrown upward on the planet mars with a velocity of 12 m/s, its height (in meters) after t seconds is given by h = 12t − 1.86t2. (a) find the velocity of the rock after two seconds. m/s (b) find the velocity of the rock when t = a. 12−3.72a m/s (c) when will the rock hit the surface? (round your answer to one decimal place.) t = s (d) with what velocity will the rock hit the surface? m/s