21. Which statement is true for limiting frictional force.
a) it is greater than rolling friction
b) it is greater that sliding friction
c) it is greater that kinetic friction
d) all are true
22. A pair of unlike parallel forces having different lines force produce———-.
a) equilibrium b) torque
c) a couple d) unstable equilibrium
23. Head to tail rule can be used to add———— forces.
a) two b) three
c) five d) any number of
24. A force of 15 N makes an angle of 60° with horizontal. Its vertical component will be:
a) 15N b) 10N
c) 13N d) 7 N
25. A body is in equilibrium when it has
a) uniform speed b) uniform acceleration
c) both a and b d) zero acceleration
26. A body is in stable equilibrium after slight tilt if its Centre of gravity
a) remains above the point of contact
b) remains on one side of point of contact
c) passes over the point of contact
d) is at lowest position
27. A body is in unstable equilibrium after slight tilt if its center of gravity
a) remains on one side of the point of contact
b) remains above the point of contact
c) passes over the point of contact
d) is positioned at its bottom
28. A body is in neutral equilibrium when its Centre of gravity
a) Is at the lowest position
b) Remains at same height
c) Is at highest position
d) Is at its base
29. Bunsen burner is made stable by
a) Increasing its length
b) Increasing its mass
c) Decreasing its base area
d) Increasing its base area
30. A tight rope walker carries a long pole to
a) Increase his weight
b) Raise his Centre of gravity
c) Lower his Centre of gravity
d) Keep his Centre of gravity in fixed position
