Question

I need help with it I don't understand this .... Can someone please help ASAP

Answer 1

Answer:

a.     h(t) = -16t^2 +12t + 4.

b.    5.04 ft

c.     6 ft.

d.    1 second.

Step-by-step explanation:

a.

This is upward motion against the force of gravity. The acceleration due to gravity is 32 ft s-2.

An equation modelling this is

h(t) = ut + 1/2 gt^2 + 4  where h(t) = height of the birdie at time t, g = acceleration due to gravity, t = the time and u = the initial velocity.

u = 12 and g = -32 (because the flight is against gravity) so we have:

h(t) = 1/2 * -32 t^2 + 12t + 4

h(t) = -16t^2 + 12t  + 4

b.  At t = 0.1 seconds the height is 12(0.1) - 16(0.1)^2 + 4

=  1.2 - 0.16 + 4

= 5.04 ft.

c. At t = 0.25 the height is 12(0.25) - 16(0.25)^2 + 4

= 6 feet

d . When the birdie reaches the ground h will be 0 so

12t - 16t^2 + 4 = 0

-4t^2 + 3t  + 1 = 0

(4t- 1)(-t - 1) = 0

t = -0.25, t = 1

t = 1   ( ignore the negative root).

t = 1 second.