Question

When gasoline is burned, it gives off 46,000 J/gram of heat energy. If an automobile uses 13.0 kg of gasoline per hour with an efficiency of 21%, what is the average horsepower output of the engine

Answer 1

the average horsepower output of the engine is 46.76 hp

Step-by-step explanation:

The computation of the average horsepower output of the engine is shown below

The output of the engine is

= (Energy content of gasoline) × (usage of the fuel ) × (Fuel efficiency)

As we know that

1 hp = 746 W

where,

Energy content of gasoline = 46000 J / g = 4.6 × 107 J/kg

Usage of the fuel = 13 kg / h = 13 ÷ 3600 kg/s

Fuel efficiency = 21% = 0.21

Therefore, the output of the engine is

= 4.6 × 107 × (13 ÷ 3600) × 0.21 × (1 ÷ 746) h.p.

= 46.76 h.p.

hence, the average horsepower output of the engine is 46.76 hp

Answer 2

The correct output will be "46.76 h.p.".

Step-by-step explanation:

The given values are:

Gasoline's energy content,

= 46000 J/g

= 4.6 x10⁷ J/kg

Fuel usage,

= 13 kg/h

=
`(13)/(3600) \ kg/s`

Fuel efficiency,

= 21%

= 0.21

Now,

The average output will be:

=
`(Energy \ content \ of \ gasoline)* (fuel \ usage)* (fuel \ efficiency)`

On substituting the values, we get

=
`4.6* 10^7* ((13)/(3600) )* 0.21* ((1)/(746)) h.p.`

=
`46.76 \ h.p.`