Given:
k = 100 lb/ft, m = 1 lb / (32.2 ft/s) = 0.03106 slugs
Solution:
F = -kx
mx" = -kx
x" + (k/m)x = 0
characteristic equation:
r^2 + k/m = 0
r = i*sqrt(k/m)
x = Asin(sqrt(k/m)t) + Bcos(sqrt(k/m)t)
ω = sqrt(k/m)
2π/T = sqrt(k/m)
T = 2π*sqrt(m/k)
T = 2π*sqrt(0.03106 slugs / 100 lb/ft)
T = 0.1107 s (period)
x(0) = 1/12 ft = 0.08333 ft
x'(0) = 0
1/12 = Asin(0) + Bcos(0)
B = 1/12 = 0.08333 ft
x' = Aω*cos(ωt) - Bω*sin(ωt)
0 = Aω*cos(0) - (1/12)ω*sin(0)
0 = Aω
A = 0
So B would be the amplitude. Therefore, the equation of motion would be x
= 0.08333*cos[(2π/0.1107)t]
Answer:
Work done, W = 1.44 kJ
Explanation:
Given that,
Mass of boy, m = 74 kg
Initial speed of boy, u = 1.6 m/s
The boy then drops through a height of 1.56 m
Final speed of boy, v = 8.5 m/s
To find,
Non-conservative work was done on the boy.
Solution,
The work done by the non conservative forces is equal to the sum of total change in kinetic energy and total change in potential energy.



W = 1447.21 Joules
or
W = 1.44 kJ
Therefore, the non conservative work done on the boy is 1.44 kJ.
Answer:
2.33 nC, 4.67 nC
Explanation:
when the two spheres are connected through the wire, the total charge (Q=7.00 nC) re-distribute to the two sphere in such a way that the two spheres are at same potential:
(1)
Keeping in mind the relationship between charge, voltage and capacitance:

we can re-write (1) as
(2)
where:
Q1, Q2 are the charges on the two spheres
C1, C2 are the capacitances of the two spheres
The capacitance of a sphere is given by

where R is the radius of the sphere. Substituting this into (2), we find
(3)
we also know that sphere 2 has twice the diameter of sphere 1, so the radius of sphere 2 is twice the radius of sphere 1:

So the eq.(3) becomes

And re-arranging it we find:

And since we know that the total charge is

we find

12 increase When force is multiplied by the distance over which it is applied, that amount is given ... force * distance = work
Answer: A.) v = 2πr/T
Explanation:
The tangential speed of an orbiting object can be obtained by the product of the radius of the orbit and the angular speed of the object in a circular motion.
This the tangential seed can be represented mathematically as :
Tangential speed (v) = angular speed(ω) × radius(r)
v = r × ω --------(1)
Recall:
ω = 2π/T
Substituting ω = 2π/T in equation (1)
v = r × 2π/T
v = 2πr/T