In a test of military ordnance, a large number of bombs were dropped on a target from various heights. The initial velocity of the bombs in the direction of the ground was 0. Let y be the height in meters from which a bomb is dropped, let x be the time in seconds for the bomb to strike the ground, let w = x², and let v = √y. The relationship between x and y is given by y = 4.9x². For each of the following pairs of variables, state whether the correlation coefficient is an appropriate summary.

a. x and y

b. w and y

c. x and v

d. w and v

e. ln x and ln y