The distance h a body will move in a free fall is expressed by the formula h = 1/2 gt 2. If g = 980 cm per

Question

The distance

h a body will move in a free fall is expressed by the formula h = 1/2 gt 2. If g = 980 cm per

sec per sec and t = 20 sec, the distance h is

A. 368,000 cm.

B. 9,800 cm.

C. 49,000 cm.

D. 196,000 cm.

Answer 1

Given that the distance, h, a body will move in a free fall is expressed by the following formula:

     h = (1/2)gt² ,   

   where g = 980 cm/sec/sec (or, g = 980 cm/sec²) and t = 20 sec 

Then to solve for h, plug in the given values into the formula above. Doing so, we arrive at the following:

     h = (1/2)(980 cm/sec/sec)(20 sec)² 

       = (1/2)(980 cm/sec²)(20² sec²)

       = (1/2)(980 cm/sec²)(400 sec²)

       = (1/2)(980)(400) cm

       = 196,000 cm    (answer choice D)