The difference in electric potential energy between the two points is

where q is the magnitude of the charge and

is the electric potential difference.
But for energy conservation, the difference in electric potential energy

between the two points is equal to the work done to move the charge between A and B:

so we have

and by substituting the numbers of the problem, we find the value of

:
Answer:
1.25kg
Explanation:
Simply multiply volume and density together
Answer:
rpm
Explanation:
Given that rotational kinetic energy = 
Mass of the fly wheel (m) = 19.7 kg
Radius of the fly wheel (r) = 0.351 m
Moment of inertia (I) = 
Rotational K.E is illustrated as 





Since 1 rpm = 



Answer:
option C
Explanation:
given,
Force on the object = 10 N
distance of push = 5 m
Work done = ?
we know,
work done is equal to Force into displacement.
W = F . s
W = 10 x 5
W = 50 J
Work done by the object when 10 N force is applied is equal to 50 J
Hence, the correct answer is option C
Answer:
The equation of motion is 

Explanation:
Lets calculate
The weight attached to the spring is 24 pounds
Acceleration due to gravity is 
Assume x , is spring stretched length is ,4 inches
Converting the length inches into feet 
The weight (W=mg) is balanced by restoring force ks at equilibrium position
mg=kx
⇒ 
The spring constant , 
= 72
If the mass is displaced from its equilibrium position by an amount x, then the differential equation is



Auxiliary equation is, 

=
Thus , the solution is 

The mass is released from the rest x'(0) = 0
=0


Therefore ,

Since , the mass is released from the rest from 4 inches
inches
feet
feet
Therefore , the equation of motion is 