Which scientist described the existence of the neutron

Which expression allows you to determine the mechanical advantage of an inclined plane? a. height of plane / input force b. length of plane / input force c. length of plane / height of plane d. height of plane / length of plane

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

Matter is needed to transfer thermal energy bya. conductionb. convectionc. radiation d. both a & b.