The height of a helicopter above the ground is given by h = 2.80t3, where h is in meters and t is in seconds. At t = 1.55 s, the helicopter releases a small mailbag. How long after its release does the mailbag reach the ground?

Question

anonymous · Answer

$$h=2.80t^3$$
plug in 1.55 to find h

anonymous · Answer

^^^thats wrong

anonymous · Answer

=/

anonymous · Answer

$$h=2.80(1.55)^{3}=10.43........ g=9.8m/s^{2}$$

anonymous · Answer

i got 10.43 as well

anonymous · Answer

9.8??

anonymous · Answer

thats just the height now use kinematic formula

anonymous · Answer

which is? lol we didnt learn this..my teacher is horrible and teach us this stuff but assigns homework

anonymous · Answer

this is why i keep coming on here for help lol bc my teacher....SUCKS

anonymous · Answer

$$t=\sqrt{\frac{10.43*2}{9.8}}=$$

anonymous · Answer

1.46?

anonymous · Answer

says thats wrong too

anonymous · Answer

=(

anonymous · Answer

whats the answer?

anonymous · Answer

doesnt tell me

anonymous · Answer

$$h=\frac{at^{2}}{2}$$

anonymous · Answer

i have one more chance to get it

anonymous · Answer

guess ill move on for now

anonymous · Answer

the answer should be 1.46 seconds

anonymous · Answer

it said no lol

stormfire1 · Answer

The answer is simple: $$10.43=1/2 g t ^{2}$$You know that g = 9.8 m/s so just solve for t.

anonymous · Answer

riptide when you enter the answer are you including the units of seconds? Or does units matter

stormfire1 · Answer

$$height=2.80t ^{3}$$$$height @ 1.55s = 2.80(1.55)^3=10.42685$$$$10.42685= 1/2 g t^2$$$$10.42685*2/9.8 = t^2$$$$t=\sqrt{2.127928571}=1.458742119$$So the previous answer posted is right...I just posted this to show all the figures/calcs.  Maybe you can figure out what's wrong from there.

anonymous · Answer

it even said 1.5 was wrong...so idk what it wants lol and it wont tell me the answer anyway