A box is held at rest by two ropes that form 30° angles with the vertical. The tension T in either rope is 42 N. What is the weight (w) of the box?

36 N

79 N

86 N

73 N

62 N

A box is held at rest by two ropes that form 30 angles with the vertical The tension T in either rope is 42 N What is the weight w of the box 36 N 79 N 86 N 73 class=

Respuesta :

Answer;

= 73 N

Explanation;

Using the formula

2 T cos(30°) = w

Where; T is the tension on each string, while w is the weight of the box given by mg

Therefore;

W = 2Tcos 30°

    = 2 × 42 cos 30°

    = 84 cos 30°

    = 72.74

  ≈ 73 N