Complete Question
The complete question is shown on the first uploaded image
Answer:
a
The tension is 
b
The time taken is 
c
The position for maximum velocity is
S = 0
d
The maximum velocity is
Explanation:
The free body for this question is shown on the second uploaded image
From the question we are told that
The mass of the bob is 
The angle is 
The length of the string is 
The tension on the string is mathematically represented as

substituting values


The motion of the bob is mathematically represented as

=> 
Where
is the angular speed
and
is the phase change
At initial position S = 0
So 

Generally
can be mathematically represented as

Where T is the period of oscillation which i mathematically represented as

So



substituting values


Looking at the equation

We see that maximum velocity of the bob will be at S = 0
i. e 
The maximum velocity is mathematically represented as

Where A is the amplitude which is mathematically represented as

So

Recall 
substituting values
Answer:
0.903 seconds
Explanation:
To find how many seconds the acorn fall, we can use the formula for distance travelled with constant acceleration:
D = Vo*t + a*t^2/2,
where D is the distance travelled, Vo is the inicial speed, t is the time and a is the acceleration.
In our problem:
Vo = 0,
a = g = 9.81 m/s2,
D = 4 meters.
So, we can solve the equation to find the time:
4 = 0*t +9.81*t^2/2
4.905*t^2 = 4
t^2 = 4/4.905 = 0.8155
t = 0.903 seconds
The correct answer to the question is : Transverse wave.
EXPLANATION :
Before going to answer this question, first we have to understand the longitudinal and transverse wave.
LONGITUDINAL WAVE : A longitudinal wave is a mechanical wave in which the direction of vibration of particles is parallel to the direction of wave propagation. It moves in the form of compression and rarefaction.
For instance, sound wave.
TRANSVERSE WAVE : A transverse wave is a mechanical wave in which the direction of vibration of particles is perpendicular to the direction of wave propagation. It moves in the form of crests and troughs.
For instance, the wave created in a pond when a stone is dropped into it.
Hence, the correct answer of this question is transverse wave.
Usually, the forces that start the oscillation of buildings are the wind and microearthquakes.