Which statement about speed and/or velocity is true?
velocity has both speed and direction.
speed is constant.
speed has direction and velocity.
speed is measured over time.

12 drag each label to the correct category. decide whether each statement describes mass or weight. measured in newtons measured in kilograms does not change when gravity changes === a gravitational force changes when gravity changes the amount of matter in something mass weight

Which of the following is the main energy source for the sun? a. fission of hydrogen b. fusion of hydrogen c. fusion of helium d. fission of iron

Which of the following is a measure of the amount of light a star directly emits?               a.  luminosity    b.  intensity    c.  wavelength    d.  brightness