Answer :
Final answer:
The speed with which the pebble strikes the ground when it is fired vertically straight up is 25 m/s.
Explanation:
To find the speed at which the pebble strikes the ground when it is fired vertically straight up, we can use energy considerations. When the pebble is at the top of the building, it possesses only potential energy. As it falls, this potential energy gets converted into kinetic energy. So, we can equate the potential energy at the top to the kinetic energy at the bottom;
mgh = 1/2 mv2
Where m is the mass of the pebble, g is the acceleration due to gravity, h is the height of the building, and v is the final velocity.
Substituting the given values, we get:
(0.2 kg)(9.8 m/s2)(36.6 m) = 1/2 (0.2 kg) v2
Simplifying, we find that v = 25 m/s. So, the speed with which the pebble strikes the ground when it is fired vertically straight up is 25 m/s.
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