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A student uses a pencil as a lever to launch a piece of trash into the trashcan. If the student positions a marker as the fulcrum just 2.8 cm from where she applies effort, and 7 cm from the piece of trash to the fulcrum, what is the mechanical advantage the lever gives?

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