True or false. As a wave travels through a given material its velocity changes.
2 answers:
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Answer:
height from where rock was thrown is 27.916 m
Explanation:
speed = 7.50 m/s
θ = 30°
g= 9.8 m/s²
horizontal distance = 18 m
time require for vertical displacement
t = 2.8 sec
now for calculation of height
s = ut + 0.5 a t²
-h = v sinθ× t + 0.5 ×(-9.8)× (2.8²)
-h = 7.5 sin30°× 2.8 - 0.5 ×(9.8)× (2.8²)
-h = -27.916 m
h= 27.916 m
height from where rock was thrown is 27.916 m
Answer:
the ratio of the heat rejected to the cold reservoir for the improved engine to that for the original engine is 0.68
Explanation:
Given information
initial efficiency, η = 0.28
final efficiency, η = 0.51
ratio of the heat rejected = (1 - η)/(1 - η
)
= (1 - 0.51)/(1 - 0.28)
= 0.68