Answer:b
Explanation:
Object will be stable if its center of gravity lies over its base of support.
If the center of gravity is above the center of buoyancy then it provides positive righting moment and the object floats over the liquid and such object is said to possess positive meta-centric height.
Answer:
The new potential energy decreases by the factor of 2 to the old potential energy.
Explanation:
Capacitance of a parallel plate capacitor is given by the relation :
C = (ε₀A)/d
Here ε₀ is vacuum permittivity, A is area of the capacitor plate and d is the distance between them.
Potential energy of the capacitor, U = 
Here V is the potential difference between the plates.
According to the problem, the distance between the plates get double but area remains same. So,
d₁ = 2d
Here d₁ is new distance between the plates.
Hence, new capacitance is :
C₁ = (ε₀A)/d₁ = (ε₀A)/2d = C/2
The capacitor have same potential difference that is V. Hence, the new potential energy is :
U₁ =
= 
U₁ = U/2

Answer:

Explanation:
The acceleration of an object (or a person, as in this case) is given by

where
v is the final velocity
u is the initial velocity
t is the time interval
In this problem,
u = 20 m/s
v = 40 m/s
t = 10 s
Therefore Jill's acceleration is

Answer:
Average velocity = 30 miles per hour
Explanation:
Given that
Velocity for uphill = 20 miles per hour
Velocity for downhill = 60 miles per hour
We know that
Distance = Velocity x time
Total distance = Average velocity x total time
Lets take distance from home to school is s
Time taken from home to school= s/20 hr
Time taken from school to home= s/60 hr
Total time =s/20+s/60
Total distance = Average velocity x total time
s + s = Average velocity x (s/20+s/60)
So average velocity = 30 miles per hour
Answer:
Explanation:
All existing matter and space considered as a whole; the cosmos. The universe is believed to be at least 10 billion light years in diameter and contains a vast number of galaxies; it has been expanding since its creation in the Big Bang about 13 billion years ago.