A snowboarder taking part in a snowboard cross competition starts from rest at the top of a slope and boards down to the bottom of the slope.



​A spectator decides to calculate the average speed of the snowboarder.

(a) ​State the quantities that need to be measured to calculate the average speed. ​ (2)

(b) ​State the apparatus required to make these measurements. ​​​ (2)

(c) ​State the equation used to calculate the average speed of the snowboarder. ​ (1)

(d) ​The snowboarder takes 56 s to travel down the 350 m from the start to the end of the slope.

Calculate the average speed of the snowboarder. ​​​​​ (3)