Which sounds can be heard safely by humans without
risking damage to the ear? Check all that apply.
O
rustling leaves
normal conversation
vacuum cleaner
front row at a rock concert
jet takeoff

These sounds can be heard safely by humans without risking permanent hearing loss:

-- rustling leaves . . . . . Yes

-- normal conversation  . . . . . Yes

-- vacuum cleaner  . . . . . Yes IF it's on the floor and you're standing up.

-- front row at a rock concert . . . . . No

-- jet takeoff . . . . . Yes BUT only if you're at least a mile away from the jet.

the answer is b ) square root of 5

answer: 802.3 kilo joules of energy represents 191.75 kilo calorie of energy.

explanation:

energy released during combustion of one mole methane = 802.3 kilo joules

if 1 kilo joule = 0.239006   kilo calorie

then ,802.3 kilo joule will be = 802.30.239006 kilo calorie

802.3 kilo joule = 191.75 kilo calorie

hence, the energy in kilo calorie is 191.75 kilo calorie.