Knowing A has the constant speed shown determine the motion

Knowing A has the constant speed shown, determine the motion (velocity and acceleration) collar B appears to have to an observer sitting at A and looking down the bar during the motion. Take x along the bar from A to B.

Solution

Collar B is fixed, So with respect to earth\'s inertial frame its velocity and accelaration is zero.
Now for an observer sitting at A and looking towards point B, He will observe that point B is moving away from him at a speed of V= 10*cos(60)=5 m/s along the x axis.

Also since speed of A is constant so accelaration observed will be zero.