A4-kg hammer is lifted to a height of 10 m and dropped from rest. what was the velocity (in m/s) of the hammer when it was at a height of 4 m from the earth? o12 o5 o11 o109.5

v = 10.84 m/s

Explanation:

using the equation of motion:

v^2 = (v0)^2 + 2×a(r - r0)

due to the hammer starting from rest, vo = 0 m/s and a = g , g is the gravitational acceleration.

v^2 = 2×g(r - r0)

v = \sqrt{2×(-9.8)×(4 - 10)}

  = 10.84 m/s

therefore, the velocity at r = 4 meters is 10.84 m/s

d. air pressure decreases as altitude increases.