## Applied Mechanics and Graphic Statics The following statement is one of the laws of Dynamic friction

All of these
The force of friction always acts in a direction opposite to that in which a body is moving
The magnitude of the kinetic friction bears a constant ratio to the normal reaction between two surfaces. The ratio being slightly less than that in the case of limiting friction
For moderate speeds the force of friction remains constant but decreases slightly with the increase of speed

## Applied Mechanics and Graphic Statics A Second's pendulum gains 2 minutes a day. To make it to keep correct time its length

Is not changed but weight of the bob is decreased
Must be increased
Is not changed but weight of the bob is increased
Must be decreased

M1L3T2
M-1L2r2
M-1L3r2
M-2L3T2

45°
30°
90°

## Applied Mechanics and Graphic Statics The maximum frictional force which comes into play, when a body just begins to slide over the surface of a another body, is known

Limiting friction
Sliding friction
None of these
Rolling friction

Maximum
Minimum
Zero
Constant