Question

A machine uplifts a load of 100 N by 10 cm. In this process, it requires 80 N of effort with downward displacement of 15 cm. Calculate:

1. mechanical advantage
2. velocity ratio
3. work input
4. efficiency of the machine

Answer 1

Given:

Load (L) = 100 N

Distance moved by load (d_L) = 10 cm = 0.1 m

Effort (E) = 80 N

Distance moved by effort (d_E) = 15 cm = 0.15 m

(i) Mechanical Advantage (MA) = `"Load (L)"/"Effort (E)"`

= `100/80`

= 1.25

(ii) Velocity Ratio (VR) = `("Distance moved by Effort" (d_E))/("Distance moved by Load" (d_L))`

= `15/10`

= 1.5

(iii) Work Input = Effort (E) × Distance moved by Effort (d_E in meters)

= 80 × 0.15

= 12 J

(iv) Efficiency of the machine (η) = `(MA)/(VR) xx 100%`

= `1.25/1.5 xx 100%`

= 0.8333 × 100%

= 83.33%