A water skier lets go of the rope at the top of a ramp, with a speed of 14m/s, The skiers speed at the highest point of the jump is 13m/s?

Call the mass m (it will cancel out).

v₁ = initial speed = 14m/s

v₂ = final speed = 13m/s

potential energy gained = kinetic energy lost

mgh = ½mv₂² - ½mv₁²

gh = ½v₂² - ½v₁²

h = ½(v₂² - v₁²)/g

It depends what value you are supposed to use for g. If we use g = 10m/s²:

h = ½(14² - 13²)/10

. .= 1.35m

If we use the more accurate value g = 9.8m/s²:

h = ½(14² - 13²)/9.8

. .= 1.38m

But if we round to 2 significant figures, it doesn't matter - we get 1.4m in both cases.