Askateboarder, coasting with a constant velocity, jumps straight up. when she lands, does she come down a.) behind the skateboard b.) ahead of the skateboard c.) on the skateboard

The correct choice is

c.) on the skateboard

before the jump, the skateboarder and skateboard both had same constant velocity in horizontal direction. the skateboarder jumps in Up direction. just after jump, the skateboarder has velocity in up direction as well as in horizontal direction. the velocity in horizontal direction is always same as the velocity of skateboard. hence the skateboarder is always above the skateboard and finally lands onto it.

it is called kinetic energy

  the unit of the measure =

explanation:

  the property that is quantified by the energy needed per of material to raise the temperature by one.

  si unit of energy = joule (j)

  si unit of temperature = kelvin (k)

  si unit of mass of material = kilogram (kg)

the property that is quantified by the energy needed per of material to raise the temperature by one is called specific heat.

the unit of specific heat is