Falling objects drop with an average acceleration of 9.8 m/sec/sec, or 9.8 m /s2. If an object falls from the top of a tall building, how long will it take before it reaches a speed of 49 m/sec?
Use the velocity expression for uniform acceleration and solve for t: v = v0 + at. v0 is zero since the object is at rest. 49 m/s = a(t), and solve for t. t = 49 m/s / 9.8 = 5 seconds.
