In this question use $g = 9.8$ m s $^{-2}$ .

A uniform plank $AB\,$ of length 6 m and mass 30 kg rests horizontally on two supports at $C\,$ and $D$ , where $A C = 1$ m and $A D = 4$ m.

A block of mass $m\,$ kg is placed on the plank at $B$ , and the plank is then on the point of tilting about $D$ .

Figure for question 7

Explain why the reaction of the support on the plank at $C\,$ is zero.

Find the value of $m$ .

Find the magnitude of the reaction of the support on the plank at $D$ .

In this question use $g = 9.8$ m s $^{-2}$ .

A uniform plank $AB\,$ of length 6 m and mass 30 kg rests horizontally on two supports at $C\,$ and $D$ , where $A C = 1$ m and $A D = 4$ m.

A block of mass $m\,$ kg is placed on the plank at $B$ , and the plank is then on the point of tilting about $D$ .

Figure for question 7

Explain why the reaction of the support on the plank at $C\,$ is zero.

Find the value of $m$ .

Find the magnitude of the reaction of the support on the plank at $D$ .

3 Mechanics

3 Mechanics Questions