Answer: The riders are subjected to 11.5 revolutions per minute
Explanation: Please see the attachments below
From the law of conservation of momentum
m1u1+ m2u2= m1v1+ m2v2
110*8+ 110*-10= 110*-10 + 110* v2
v2= 8 m/sec
To reduce friction between two surfaces, you have to
make the surfaces smoother.
The best way to do that is to introduce a fluid between them,
like grease, oil, or air.
Answer:
Induced emf, 
Explanation:
Given that,
Length of the helicopter, l = 4 m
Angular speed of the helicopter, 
The vertical component of the Earth’s magnetic field is, 
We need to find the induced emf between the tip of a blade and the hub. The induced emf in terms of angular velocity of an rotating object is given by :



So, the induced emf between the tip of a blade and the hub is
. Hence, this is the required solution.
They made me do it I don’t even know what to say I’m so sorry