If the work put into a lever is 930 joules and the work accomplished is 870 joules, the efficiency of the lever is
107%
100%
94%
60%

The correct answer to this question is C) 94%.

CALCULATION:

As per the question, the work put into a lever is 930 Joule.

Hence, input work W = 930 Joule.

Work accomplished by the lever is 870 Joule.

Hence, the output work W' = 870 Joule.

We are asked to calculate the efficiency of the level.

The efficiency of the lever is defined as the ratio of output work to the input work.

Mathematically efficiency

       In percentage, efficiency

                                                                    [ans]

Hence, the efficiency of the lever is 94%.

the box does not move because you need to use a force greater than 300 n. you are only using 50 n. it needs to at least be 301 n for the box to move because then it is an unbalanced force and it will move the way that the greater force is pushing it. if you use only 300 n it will be a balanced force and will not move because the force you are exerting on the   box is the same as its force.

hope this !

im sorry if i went too in depth, i am going to include a link to a video on khan academy that will explain this.   hope that you like the video and that it explains more in detail to you.

that is the link.