Atoy rocket is launched straight up by using a spring. the rocket is initially pressed down on the spring so that the spring is compressed by 9 cm. if the spring constant is 830 n/m and the mass of the rocket is 50 g, how high will the rocket go? you may neglect the effects of air resistance. a 14.48 m b 6.86 m c 10.84 m d 3.91 m e 8.03 m

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