Question

3. Suppose the velocity, v, of an object is given by

v=2t² -5t-12
where t is time in seconds. Find the intervals where
the velocity is positive.

Answer 1

4

Explanation:

Using,

`\frac{ - b + - \sqrt{ b^(2) - 4ac} }{2a}`

Where,

A= 2

B= -5

C= -12

By substitution, you get,

`\frac{ 5 + - \sqrt{ 5^(2) - 4 * 2 * (- 12)} }{2 * 2}`

By doing the calculation you get,

`( 5 + - √(121) )/(4)`

Find the solution of both,

`( 5 + √(121) )/(4)`

AND

`( 5 - √(121) )/(4)`

t= 4 seconds OR (t= -1.5 seconds, NP)

So t=4