Answer:
84.4 %
Explanation:
Mechanical efficiency = output work/input work × 100 %
output work = 432 J of work for the bike to turn the gears
input work = 512 J of work to ride.
Mechanical efficiency = 432 J/512 J × 100 %
= 0.844 × 100%
= 84.4 %
Answer:

Explanation:
a. Internal energy and the relative specific volume at
are determined from A-17:
.
The relative specific volume at
is calculated from the compression ratio:

#from this, the temperature and enthalpy at state 2,
can be determined using interpolations
and
. The specific volume at
can then be determined as:

Specific volume,
:

The pressures at
is:

.The thermal efficiency=> maximum temperature at
can be obtained from the expansion work at constant pressure during 

b.Relative SV and enthalpy at
are obtained for the given temperature with interpolation with data from A-17 :
Relative SV at
is

=
Thermal efficiency occurs when the heat loss is equal to the internal energy decrease and heat gain equal to enthalpy increase;

Hence, the thermal efficiency is 0.563
c. The mean relative pressure is calculated from its standard definition:

Hence, the mean effective relative pressure is 674.95kPa
The gravitational force on the woman is A) 500 N
Explanation:
There are two forces acting on the woman during her fall:
- The force of gravity,
, acting downward - The air resistance,
, acting upward
According to Newton's second law, the net force acting on the woman is equal to the product between the woman's mass and her acceleration:

where m is the mass of the woman and a her acceleration.
The net force can be written as

Also, we know that the woman falls at a constant velocity (5 m/s), this means that her acceleration is zero:

Combining the equations together, we get:

which means that the magnitude of the gravitational force is equal to the magnitude of the air resistance:

Learn more about forces and Newton's second law:
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Answer:
Safety
Explanation:
Expressways are banked to resist centifugal action