Initial Velocity of the original superman

[LunaFlores]

Homework Statement

The original superman leaps into the air to land on an 85.5 m high building. What was his intial velocity?
d = 85.5 m
v2 = 0
v1 = ?
a = 9.8 m/s2 (I'm not sure about this one so I just used acceleration due to gravity)

Homework Equations

v2 = v1 + 2ad (?)

The Attempt at a Solution

I'm really not sure what acceleration value to use for this or if I can solve it without using acceleration

 

[SteamKing]

Homework Statement

The original superman leaps into the air to land on an 85.5 m high building. What was his intial velocity?
d = 85.5 m
v2 = 0
v1 = ?
a = 9.8 m/s2 (I'm not sure about this one so I just used acceleration due to gravity)

Homework Equations

v2 = v1 + 2ad (?)

The Attempt at a Solution

I'm really not sure what acceleration value to use for this or if I can solve it without using acceleration

Unless Superman is on the Planet Krypton, you should use the acceleration due to gravity here on Earth, but make sure it has the proper sign.

Since he's leaping from the ground, it's approximately correct to say that Superman's acceleration can be taken as zero, since once his feet are in the air, he can no longer provide any additional force on the ground to increase his velocity.

 

[LunaFlores]

Thank you!