Answer:
4.36 rad/s
Explanation:
Radius of platform r = 2.97 m
rotational inertia I = 358 kg·m^2
Initial angular speed w = 1.96 rad/s
Mass of student m = 69.5 kg
Rotational inertia of student at the rim = mr^2 = 69.5 x 2.97^2 = 613.05 kg.m^2
Therefore initial rotational momentum of system = w( Ip + Is)
= 1.96 x (358 + 613.05)
= 1903.258 kg.rad.m^2/s
When she walks to a radius of 1.06 m
I = mr^2 = 69.5 x 1.06^2 = 78.09 kg·m^2
Rotational momentuem of system = w(358 + 78.09) = 436.09w
Due to conservation of momentum, we equate both momenta
436.09w = 1903.258
w = 4.36 rad/s
A. Since it does not say the ball is moving your answer is A.
Answer:
164.2°
Explanation:
speed of wind (w) = 45 km/h due south
speed of aircraft (a) = 165 km/h
in what direction (in degrees) should the aircraft head in so as to fly due west?
To get the direction the pilot should fly, we can form a triangle with the data available where
- the direction of the wind (due south) serves as the opposite side
- the direction the pilot would have to fly so he can end up at he west serves as the hypothenuse
- θ is the angle between the direction the pilot would have to fly and the direction the pilot wishes to fly.
- the direction the pilot wishes to fly ( west) will serve as the adjacent side
- all this can be seen from the attached diagram.
now sin θ = 
sin θ = 
θ =
0.2728
θ = 15.8°
since we are to use the counter-clockwise from east convention our measurement would have to be taken anticlockwise from the east direction, therefore the direction of the aircraft (Ф) = 180-15.8 = 164.2°
Newtons first law is that an Object that is in motion will stay in motion until an unbalanced force acts upon it, and part 2 is that an object at rest will stay at rest until and unbalanced force acts upon it