When you drop a penny off the roof of a building, it takes 10 seconds to reach the ground. how high is the roof?

Height of roof is 490 meter.

Given that;

Time taken by coin to reach ground = 10 Seconds

Find:

Height of roof

Computation:

Using seconds equation of motion

s = ut + (1/2)(g)(t²)

s = (0)(10) + (1/2)(9.8)(10²)

s = (4.9)(100)

s = 490 meter

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D = (1/2) (g) (t²)  <== Memorize this. All the rest is just arithmetic.

D = (1/2) (9.8 m/s²) (100 s²)

D = (1/2 x 9.8 x 100) (m-s²/s²)

D = (4.9 x 100) m

D = 490 meters

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