Answer:
581 kJ, work was done by the system
Explanation:
According to the first law of thermodynamics:

where
is the change in internal energy of the system
Q is the heat absorbed by the system (positive if absorbed, negative if released)
W is the work done by the system (positive if done by the system, negative if done by the surrounding)
In this problem,


Therefore the work done by the system is

And the positive sign means the work is done BY the system.
Voltage (V)= Current (I) * Resistance (R)
I=V/R=140/2=70A
Hope this helps!
Answer:

Explanation:
mass of the bicycle + cyclist = 50 kg
constant speed = 6 km/h
a cyclist coasting down a 5.0° incline
the downward velocity is constant, so net acceleration must be zero
the air drag must be equal to gravitational force downward along the ramp
now for upward motion





Answer:
Flow rate 2.34 m3/s
Diameter 0.754 m
Explanation:
Assuming steady flow, the volume flow rate along the pipe will always be constant, and equals to the product of flow speed and cross-section area.
The area at the well head is

So the volume flow rate along the pipe is

We can use the similar logic to find the cross-section area at the refinery

The radius of the pipe at the refinery is:



So the diameter is twice the radius = 0.38*2 = 0.754m
The answer to this question is dropping it on a hard surface.