Question

Select the best answer to the word problem (Picture provided)

Answer 1

Answer:

The answer is $L_{t}=0.5L_{0}$ ⇒ answer (b)

Step-by-step explanation:

* Lets discuss the formula

- cosФ =$\sqrt{\frac{L_{t}}{L_{0}}}$

- Now find $L_{t}$ in termas of cosФ and $L_{0}$

* square the two sides

∴ cos²Ф = $\frac{L_{t}}{L_{0}}$

* Multiply two sides by $L_{0}$

∴ cos²Ф × $L_{0}$ = $L_{t}$

∵ Ф = 45°

∴ $L_{t}=cos^{2}45(L_{0})$

∵ cos45 = √2/2

∴ cos²Ф = (√2/2)² = 1/2 = 0.5

∴ $L_{t}=0.5L_{0}$