10
1 Kinematics and Statics
Fig. 1.8b
1.41 A container of mass 200 kg rests on the back of an open truck. If the truck
accelerates at 1.5 m/s 2 , what is the minimum coefficient of static friction
between the container and the bed of the truck required to prevent the container from sliding off the back of the truck?
[University of Manchester 2007]
1.42 A wheel of radius r and weight W is to be raised over an obstacle of height
h by a horizontal force F applied to the centre. Find the minimum value of F
(Fig. 1.9).
Fig. 1.9
1.2.5 Centre of Mass
1.43 A thin uniform wire is bent into a semicircle of radius R. Locate the centre of
mass from the diameter of the semicircle.
1.44 Find the centre of mass of a semicircular disc of radius R and of uniform
density.
1.45 Locate the centre of mass of a uniform solid hemisphere of radius R from the
centre of the base of the hemisphere along the axis of symmetry.
1.46 A thin circular disc of uniform density is of radius R. A circular hole of
radius ½R is cut from the disc and touching the disc’s circumference as in
Fig. 1.10. Find the centre of mass.