Answer:
16m/s
Explanation:



Therefore, the speed after 8 seconds is 16m/s
Answer:
The capacitance per unit length is 
(b) is correct option.
Explanation:
Given that,
Radius a= 2.50 mm
Radius b=7.50 mm
Dielectric constant = 3.68
Potential difference = 120 V
We need to calculate charge per length for the capacitance
Using formula of charge per length

Put the value into the formula


We know that,

We need to calculate the capacitance per unit length
Using formula of capacitance per unit length



Hence, The capacitance per unit length is 
Answer:
, assuming that the gravitational field strength is
.
Explanation:
Notice that both the speed and the direction of motion of this block are constant. In other words, the velocity of this block is constant.
By Newton's Second Law, the net force on this block would be
. External forces on this block should be balanced. Thus, the magnitude of the (downward) weight of this block should be equal to the magnitude of the (upward) force that the boy applies on this block.
Let
denote the mass of this block. It is given that
. The weight of this block would be:
.
Hence, the force that the boy applies on this block would be upward with a magnitude of
.
The mechanical work that a force did is equal to the product of:
- the magnitude of the force, and
- the displacement of the object in the direction of the force.
The displacement of this block (upward by
) is in the same direction as the (upward) force that this boy had applied. Thus, the work that this boy had done would be the product of:
- the magnitude of the force that this boy exerted,
, and - the displacement of this block in the direction,
.
.
Answer:
The permittivity of rubber is 
Explanation:
From the question we are told that
The magnitude of the point charge is 
The diameter of the rubber shell is 
The Electric field inside the rubber shell is 
The radius of the rubber is mathematically evaluated as

Generally the electric field for a point is in an insulator(rubber) is mathematically represented as
Where
is the permittivity of rubber
=> 
=> 
substituting values

