Algebra 1 Word Problem Help?

Question

A dog jumps off the ground with an initial velocity of 4 feet per second. A)Write an equation that gives the height in feet of the dog as a function of the time in seconds since it jumps.                                         B) After how many seconds does the dog land on the ground?

 

Answer 1

The acceleration due to gravity is -32 ft/sec.  The position of the dog can be shown by:

 

4t + 1/2(-32)t²  where  t is time in seconds  simplified:

 

-16t² + 4t

 

Too find when he hits the ground set the equation = 0 and solve for t

 

-16t² + 4t = 0

 

-4t(4t - 1)=0  which occurs at time 0 (when the dog first leaps) and again 1/4 when he hits the ground