Find speed using distance and acceleration?

[bear_neals]

Hi everyone,
hopefully someone hear can help me.

a man jumps into a swimming pool from a height of 4.7m assuming that his downward acceleration is 9.8 m s² due to gravity, at what speed does he enter the water.

I really need help knowing what equations to use, i realize i need to work out the time taken and use that to calculate the overall speed but i am having trouble displaying that as i need to show all my workings.

Thanks for your time.

 

[srmico]

You could use the formula (distance)=(initial velocity)*t + (1/2)*(acceleration)*t^2 to find the time, using initial velocity = 0, acceleration = -9.8 and distance = 4.7.

Then you could use the formula (final velocity)-(initial velocity) = (acceleration)*t, using the same acceleration and time. Dont forget the negative sign in both accelerations.

Hope this helped.