Answer:
3 units
Solution:
V=539 cubic units
Square base, with edge a=7 units
Slanted edge length: s=14 units
V=Ab h
Ab=49 square units
539 cubic units = (49 square units) h
h= 11 units
s-h=14 units-11 units
s-h=3 units
First,

where
is density,
is mass, and
is volume. We can compute the volume of the roll:


When the roll is unfurled, the aluminum will be a rectangular box (a very thin one), so its volume will be the product of the given area and its thickness
. Note that we're assuming the given area is not the actual total surface area of the aluminum box, but just the area of the largest face (i.e. the area of one side of the unrolled sheet of aluminum).
So we have

where
is the given area, so


If we're taking significant digits into account, the volume we found would have been
, in turn making the thickness
.
1. its must be B and 2. must be C
Answer:
(A) ratio of electric force to weight will be 
(b) Electric field will be 
Explanation:
We have given mass of bee = 100 mg = 
Charge on bee 
Electric field E = 100 N/C
Weight of the bee 
Electric force on the bee 
So the ratio of electric force on the bee and weight is 
(B) To hold the bee in air electric force must be equal to weight of bee
So 


To solve this problem it is necessary to apply the concepts related to Kinetic Energy, specifically, since it is a body with angular movement, the kinetic rotational energy. Recall that kinetic energy is defined as the work necessary to accelerate a body of a given mass from rest to the indicated speed.
Mathematically it can be expressed as,

Where
I = Moment of Inertia
Angular velocity
Our values are given as

A revolution is made every 4.4 seconds.


If the angular velocity is equivalent to the displacement over the time it takes to perform it then


Replacing at our previous equation we have,



Therefore the kinetic energy is equal to 