Aknight sits on a castle wall during a siege. to while away the time, he notes that boulders catapulted from below land on the top of his wall with a vertical velocity of 5.6 m/s. if he is 39 m above the catapult, what is the initial velocity of the boulders? the acceleration of gravity is 9.8 m/s 2 . answer in units of m/s.

v = 28.21 m/s

Explanation:

given,

vertical velocity of the boulder = 5.6 m/s

height of catapult = 39 m

initial velocity = ?

acceleration due to gravity = 9.8 m/s²

maximum height attained

v² = u² + 2 as

5.6² =  = 2 g h

h = 1.6 m

total height above catapulted

H = 39 + 1.6 = 40.6 m

v = 28.21 m/s

so the intial velocity is equal to v = 28.21 m/s

as technology advances, new experiments often expose problems in accepted theories. c

hope i

-lavira: )

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.