Answer:
A and B
Explanation:
Because both of them have only magnitude not direction.
The Huns' invasion of Europe caused a mass migration driving Germanic tribes of Northern Europe to the borders of the Roman Empire which led to the Barbarian attacks on Rome.
Potential energy = (weight) x (height)
After the car has been raised 2.5 meters, it has
(11,000) x (2.5) = 27,500 Joules
MORE potential energy than it had before it was lifted.
That's the energy that has to come from the work you do to lift it.
Since no mechanical process is ever 100% efficient, the work required
to accomplish this task is <em>at least 27,500 joules</em>.
Answer:
When air resistance equals the weight of an object, the object has reached free fall.
Explanation:
- When an object has only force acting on it as gravity then, it experiences free fall.
- During free fall all the forces except gravity is balanced by one another.
- In the question, object's weight is balanced by air resistance so it is in the state of free fall.
- At the null point of free fall, object experiences weightlessness i.e. it feels like object is not attracted by any force.
Answer:
Hi
Final temperature = 250.11 °C
Final volume = 0,1 m3.
Process work = 0
Explanation:
The specific volume in the initial state is: v = 0.1m3/2 kg = 0.05 m3/kg.
This volume is located between the volumes as saturated liquid and saturated steam at 20 °C. For this reason the water is initially in a liquid vapor mixture. As the piston was blocked the volume remains constant and the process is isometric, also known as isocoric process, so the final temperature will be the water temperature at a saturated steam of v=0.05m3/kg, which is obtained by using steam tables for water, by linear interpolation. As follows, using table A-4 of the Cengel book 7th Edition:
v=0.05 m3/kg
v1=0.057061 m3/kg
T1=242.56°C
v2=0.049779 m3/kg
T2=250.35°C
T=
The process work is zero because there is no change in volume during heating:
W=PxΔv=Px0=0
where
W=process work
P=pressure
Δv=change of volume, is zero because the piston was blocked so the volume remains constant.