Answer:
Work done = 13605.44
Explanation:
Data provided in the question:
For elongation of 2.1 cm (0.021 m) work done by the spring is 3.0 J
The relation between Energy (U) and the elongation (s) is given as:
U =
................(1)
where,
k is the spring constant
on substituting the valeus in the above equation, we get
3.0 = 
or
k = 13605.44 N/m
now
for the elongation x = 2.1 + 4.1 = 6.2 cm = 0.062 m
using the equation 1, we have
U = 
or
U = 26.149 J
Also,
Work done = change in energy
or
W = 26.149 - 3.0 = 23.149 J
Force=mass*acceleration
F=ma
F=25*5
F=100 N
Answer:
1 C
Explanation:
The intensity of electric current is defined as

where
I is the current
q is the amount of charge transferred
t is the time interval during which the charge is transferred
For the lightning in this problem, we have
is the current
is the time interval
Solving the formula for q, we find the amount of charge transferred:
