contestada

An electric motor has a rating of 4.0 × 10^2 watts.
How much time will it take for this motor to lift a
50.-kilogram mass a vertical distance of 8.0 meters?
[Assume 100% efficiency.]
(1) 0.98 s (3) 98 s
(2) 9.8 s (4) 980 s

Respuesta :

     The energy expended during move can be calculated using the Definition of Work, that is given by:

[tex]E=P\Delta S[/tex]
 
     Using the Definition of Potence, comes:

[tex]P_{ot}= \frac{P}{\Delta t} \\ \Delta t = \frac{P\Delta S}{P_{ot}}[/tex]
 
     Entering the unknowns, we have:

[tex]\Delta t = \frac{P\Delta S}{P_{ot}} \\ \Delta t = \frac{50*9.8*8}{4*10^2} \\ \boxed {\Delta t =9.8s}[/tex]

Number 2

If you notice any mistake in my english, please let me know, because i am not native.

Otras preguntas