A golf ball is hit horizontally off the edge of a 20 m high cliff and lands a distance of 18 m from the edge of the cliff. What was the initial vertical velocity of the ball? 0 m/s
16 m/s
-16 m/s
40 m/s

None of the options are correct.

Explanation:

Let be the initial horizontal velocity of the golf ball t be the time of flight.

The time of flight, t, is the time taken by the ball to touch the ground. The ball falls towards earth due to gravitational force which acts vertically downward, so, the horizontal velocity of the ball remains unchanged.

As the horizontal distance covered by the ball is 18 m,

As distance = speed x time, so

Now, by using the equation of motion in the gravitational field,

Here, u is the initial velocity in the vertical direction, s is the displacement traveled in time t, g=9.81 is the acceleration due to gravity.

Here, we have u=0, s=20 m (height of the cliff), .

seconds  (approx)

From equation (i), e have

m/s.

So, the initial velocity of the ball is 9m/s in the hprizontal diection.

Hence, none of the options are correct.

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.

it breaks and dirupture other materials and other sencews from the bottom