Answer:
w=255
Explanation:
The change in internal energy is given by the first law:
ΔE = Q - w
where ΔE is the change in internal energy of the system
q is the heat added to the system
w is the work done *by* the system on the surroundings
So, for the first phase of this process:
ΔE = Q - w
Q=160J
w=309J
ΔE = 160J - 309J = -149J
To bring the system back to its initial state after this, the internal energy must change by +149J (the system myst gain back the 149 J of energy it lost). We are told that the system loses 106 J of heat in returning to its initial state, so the work involved is given by:
ΔE = Q - w
+149J = -106J - w
255J = -w
w = -255J
Answer:
The distance from the airport to the corporate offices is 110 miles.
Explanation:
Let d be the distance from the airport to the office (at a velocity of 75 mph), the person travels an entire distance of 156 miles, 156-d is the distance from home to the airport (at a velocity of 30 mph).
The equaiton for velocity is:
From this you can find the equation for the time:
You can use the total time to find the distance d because you know that the time between the home and the airport plus the time between the airport and the work is 3 hours:
You can solve the equation to find d:
Now you have that the distance between the airport and the office is 110 miles.
Answer:
63.0 N
Explanation:
We need to consider the resultant of the forces acting along the surface. We have two forces:
- The component of the pull parallel to the ground, which is given by
where is the angle between the force and the ground
- The frictional force, given by
where is the coefficient of friction, m = 20 kg is the mass of the box and g=9.8 m/s^2.
The box is moving at constant velocity, this means zero acceleration, so the equation of equilibrium becomes:
From which we can find the magnitude of the pull, F: