Question

A force of 11 N is applied to the handle of a screwdriver being used to pry off the lid of a paint can. As the input force moves through a distance 0.3 m, the screwdriver does 3 J of work on the lid. What is the efficiency of the screwdriver? Show your work

Answer 1

Answer : The efficiency of the screwdriver is
`90.91\%`

Explanation :

Applied force on the handle of screwdriver, F = 11 N

Distance covered by the input force, d = 0.3 m

Output work,
`W_o=3\ J`

Efficiency of the screwdriver is given by the following relation :

`E=(W_o)/(W_i)* 100`

`E=(3\ J)/(11\ N* 0.3\ m)* 100`

`E=90.91\%`

Hence, this is the required solution.

Answer 2

joules =mass over a distance
11N*0.3m=3.3 Joules
efficiency= energy out/energy in *100%
energy out =energy of the tool=3 J
Energy in = added energy (man)=3.3 J
3/3.3*100%=90.91%