If a ball rolls off a 4m high table at 7m/s, how long will it take until it hits the floor

0.9 s

Explanation:

Given (vertical direction):

y₀ = 4 m

y = 0 m

v₀ = 0 m/s

a = -9.8 m/s²

Find: t

y = y₀ + v₀ t + ½ at²

(0 m) = (4 m) + (0 m/s) t + ½ (-9.8 m/s²) t²

t ≈ 0.9 s

hey , the answer is c

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.