Answer:
Explanation:
This is the case of forced oscillation . The pendulum having the same or matching time period or angular frequency with that of angular frequency of external periodic force , will be in resonance having largest amplitude.
Angular frequency of pendulum having length .9 m
= 
l = .9
angular frequency
= 
= 3.33 rad / s
If we calculate angular frequencies of pendulum of all lengths given , we will find that other lengths do not give angular frequency falling between 2 and 4 radian . So only pendulum having length of .9 m will have vibration of maximum amplitude.
Answer:
Explanation:
A body under concurrent forces (concurrent forces are forces with their line of action acting at a point) is said to be in equilibrium if the sum total of the forces acting on the body is zero.
For forces acting on a balance, the sum of upward forces and the downward forced acting on the balance must be equal for the balance to be in equilibrium.
Also the sum of clockwise moment must be equal to the sum of anticlockwise moment acting on the balance.
Moment is the product of force and the perpendicular distance from the force to the pivot.
The difference between rotational motion and circular
motion is that rotational motion is the rotation of a body about it center
mass. The axis of rotation and the center mass could change. For circular
motion, the axis of rotation and the center mass does no change.
