Question

6) A body of weight 5880 N lying on a wooden plank with an inclination of 1 in 2. the co efficient of friction is 0.25. state if the body will rest on the plank or not. If the body moves down, what force parallel to the plank is necessary to hold it back?​

Answer 1

Let, Breadth of rectangle be x m.

And, Length of rectangle be 3x + 5 m. [We take length be 3x + 5 m because it is given that length is five meter more than thrice the Breadth.]

We know,

Perimeter of rectangle = 2(Length + breadth)

Put the values :

⟶ 74= 2×(3x + 5 + x)

⟶ 74 = 6x + 10 + 2x

⟶ 74 = 8x + 10

⟶ 74 - 10 = 8x

⟶ 64 = 8x

⟶ 64/8 = x

⟶ x = 8

Verification:-

⟶ 74 = 2× (3x + 5 + x)

Put x = 8

⟶ 74 = 2×(3×8 + 5 + 8)

⟶ 74 = 2×(24 + 5 + 8)

⟶ 74 = 2×(29 + 8)

⟶ 74 = 58 + 16

⟶ 74 = 74

Now,

We take,

Breadth be x. So, Breadth of rectangle is 8 m.

Length be 3x + 5 = 3×8 + 5 = 29. Thus, Length of rectangle is 29 m.