Question

A penny is dropped from the top of the Chrysler Building (320m high). How fast is it moving when it hits the ground?

Answer 1

Once again I suppose we have to ignore air resiustance.

It seems to me that a question set on such a grand scale should explicitly state this.

The formula for motion under constant acceleration (e.g. gravity) that you need in this case is

v^2 = u^2 + 2 as

v= final velocity
u = initial velocity (= 0 in this case)
a = acceleration of gravity (= 9.81 m/s^2)
s = distance travelled (= 320m in this case)

so put these into the equation and solve for v

Answer 2

i got 25.01? but that is not the answer @MrNood

Answer 3

No - that's not correct

the value you want is v

\[v ^{2}=u ^{2}+ 2 a s\]

u = 0
a = 9.81 m/s^2
s= 320 m