Question

A falling object travels a distance given by the formula

d = 5t + 16t2,
where t is measured in seconds and d is measured in feet. How long will it take for the object to travel 21 ft?

Answer 1

The time taken by object to travel 21 ft is 1 sec

Explanation:

The distance travel by falling object given as

d = 5 t + 16 t²

The Distance cover by object to travel = 21 ft

so , from Distance time equation

21 = 5 t + 16 t²

or, 16 t² + 5 t - 21 = 0

Or, 16 t² - 16 t +21 t - 21 = 0

Or, 16 t ( t - 1) + 21 (t - 1) = 0

Or. (t - 1) (16 t + 21) = 0

Or, (t - 1) = 0 And (16 t + 21) = 0

∴ t = 1 And t = (
`(-21)/(16)` )

Hence The time taken by object to travel 21 ft is 1 sec Answer