Question

The crowbar is a type of lever as shown in the figure. A crowbar is of $$150cm$$ length. Its fulcrum is at a distance of $$50cm$$ from the load. Find out the mechanical advantage.

Answer 1

Hint: In order to solve this question, we are going to first define what a crowbar is, then, the lengths that are given are discussed and the length of the load arms and the effort arms are given then, the mechanical equivalent is calculated from the formula for the mechanical equivalent of levers.

Formula used: The mechanical advantage is given by the formula:
$$MA={\displaystyle \frac{lengthofeffortarm}{lengthofloadarm}}$$

Complete step by step answer:
A crowbar, also called a wrecking bar is a tool consisting of a metal bar with a single curved end and flattened points, often with a small fissure on one or both ends for removing nails or to force apart two objects. Crowbars are commonly used to open nailed wooden crates or pry apart boards.
It is given in the question that the length of the crowbar is equal to$$150cm$$, i.e.
$$l=150cm$$
Also, the distance of the fulcrum from the load is equal to$$50cm$$, i.e.,
$$d=50cm$$
In other words we can write that the length of load arm is $$50cm$$
And the length of the effort arm can be calculated as: $$150-50=100cm$$
Now, the mechanical advantage is given by the formula:
$$MA={\displaystyle \frac{\text{length of effort arm}}{\text{length of load arm}}}$$
Putting these values in the above equation, we get
$$MA={\displaystyle \frac{100}{50}}=2$$

Note: It is important to note that the length of the load arm is the one that gives the distance between the load and the fulcrum while the length of the effort arm is the one that is obtained by subtracting the length of the crowbar and the length of the load arm. Both are to be determined carefully to answer the question.