Acar traveling at 6.5 ms accelerates

Work out sian speed for the first 30 minutes of her journey. give your answer in km/h.

Could someone me find the answer to this problem.

Light from a sodium lamp passes through a diffraction grating that has 1000 slits per millimeter. the interference pattern is viewed on a screen 1.000 m behind the grating. the first (m = 1) two bright yellow fringes that are visible are 0.7288 m and 0.7300 m from the central maximum. what are the wavelengths of these two fringes?