Answer:
B) 100 J
Explanation:
Assuming the distance given is measured along the incline, the vertical change in height is (5 m)(sin 30°) = 2.5 m. Then the change in potential energy is ...
∆PE = mg(∆h) = (4 kg)(10 m/s^2)(2.5 m) = 100 J
Given:
The speed of sound is 340 m/s
Time for the echo is 5.2 s.
Let h = the depth of the canyon.
Because the sound of your voice travels to the bottom of the canyon and back to your ear, the total distance traveled is 2h.
By definition,
distance = velocity * time.
Therefore
2h = (340 m/s)*(5.2 s) = 1768 m
h = 884 m
Answer: The depth is 884 m.
