The third one looks correct to me
Answer:
angular speed = 0.4 rad/s
Explanation:
given data
radius = 5 m
moment of inertia = 2000 kg-m²
angular speed = 1.0 rad/s
mass = 60 kg
to find out
angular speed
solution
Rotational momentum of merry-go-round = I?
we get here momentum that is express as
momentum = 2000 × 1
momentum = 2000 kg-m²/s
and
Inertia of people will be here as
Inertia of people = mr² = 60 × 5²
Inertia of people = 1500 kg-m²
so Inertia of people for two people
1500 × 2 = 3000
and
now conserving angular momentum(ω)
moment of inertia × angular speed = ( momentum + Inertia of people ) angular momentum
2000 × 1 = (2000 + 3000 ) ω
solve we get now
ω = 0.4 rad/s
Answer:
245.45km in a direction 21.45° west of north from city A
Explanation:
Let's place the origin of a coordinate system at city A.
The final position of the airplane is given by:
rf = ra + rb + rc where ra, rb and rc are the vectors of the relative displacements the airplane has made. If we separate this equation into its x and y coordinates:
rfX = raX+ rbX + rcX = 175*cos(30)-150*sin(20)-190 = -89.75km
rfY = raY + rbY + rcT = 175*sin(30)+150*cos(20) = 228.45km
The module of this position is:

And the angle measure from the y-axis is:

So the answer is 245.45km in a direction 21.45° west of north from city A