Answer:
a)
, b)
,
, 
Explanation:
a) The system mass-spring is well described by the following equation of equilibrium:

After some handling in physical and mathematical definition, the following non-homogeneous second-order linear differential equation:
The solution of this equation is:

The velocity function is:

Initial conditions are:

Equations at
are:

The spring constant is:


After some algebraic handling, amplitude and phase angle are found:


The position can be described by this function:

b) The period of the motion is:


The amplitude is:

The phase of the motion is:

Answer:
0.08735 kgm²
Explanation:
m = Mass of lower leg = 5 kg
L = Length of leg = 18 cm
g = Acceleration due to gravity = 9.81 m/s²
f = Frequency = 1.6 Hz
I = Moment of inertia
Time period is given by

Also

So,

The moment of inertia of the lower leg is 0.08735 kgm²
Answer:
Focal Length = 38.61cm, Power = 2.59 Diopter, Converging lens.
Explanation:
When an object is placed 25cm from Gbenga's eye, the glasses lens must produce an image 61cm away (Gbenga's eye near point).
An image 61cm from the eye will be (61cm - 1.6cm) from the glasses.
i.e.
and 
note
will be negative because the image is formed on the same side as the object.
finally, 
the formula for finding the focal length
is given as




The focal length is positive which indicates converging lens
power 
but
must be in metres
Therefore, 


Answer:
Explanation:
a )
momentum of baseball before collision
mass x velocity
= .145 x 30.5
= 4.4225 kg m /s
momentum of brick after collision
= 5.75 x 1.1
= 6.325 kg m/s
Applying conservation of momentum
4.4225 + 0 = .145 x v + 6.325 , v is velocity of baseball after collision.
v = - 13.12 m / s
b )
kinetic energy of baseball before collision = 1/2 mv²
= .5 x .145 x 30.5²
= 67.44 J
Total kinetic energy before collision = 67.44 J
c )
kinetic energy of baseball after collision = 1/2 x .145 x 13.12²
= 12.48 J .
kinetic energy of brick after collision
= .5 x 5.75 x 1.1²
= 3.48 J
Total kinetic energy after collision
= 15.96 J
Answer:
Doppler effect
Explanation:
this means that at one point when the person running is close to the observer it will appear to run fast but slower as he moves away from the observer