Sound waves in air are a series of <span>periodic disturbances, </span><span>periodic condensations and rarefactions,</span><span> and high- and low-pressure regions. It is all of the above. The answer is letter D.</span>
Answer:
c) those caused by parasites
Answer:

Explanation:
m = Mass of roller coaster = 2000 kg
r = Radius of loop = 24 m
v = Velocity of roller coaster = 18 m/s
g = Acceleration due to gravity = 
Normal force at the point will be

The force exerted on the track is
.
Answer:
a.52.9 km/h
b.90 km
Explanation:
We are given that






Time spend on eating lunch and buying ga=15 min.
a.Total time=30+12+45+15=102 minute=
1 hour=60 minutes
Distance=



Total distance=
Average speed=
Using the formula
Average speed=
b.Total distance between the initial and final city lies along the route=90 km