Answer:
|v| = 8.7 cm/s
Explanation:
given:
mass m = 4 kg
spring constant k = 1 N/cm = 100 N/m
at time t = 0:
amplitude A = 0.02m
unknown: velocity v at position y = 0.01 m

1. Finding Ф from the initial conditions:

2. Finding time t at position y = 1 cm:

3. Find velocity v at time t from equation 2:

Answer:
Maximum height the atmosphere pressure can support the
water=10.336 m
Explanation:
We know that ,

Case 1 - Mercury in the tube

Case 2 - Water in the tube

Since atmospheric pressure is same
.
or, 

∴ 
Hence height of the water column =10.336 m
The resultant static friction force is equal to 20 N to the left.
Why?
I'm assuming that you forgot to write the question of the exercise, so, I will try to complete it:
"A 50-n crate sits on a horizontal floor where the coefficient of static friction between the crate and the floor is 0.50 . A 20-n force is applied to the crate acting to the right. What is the resulting static friction force acting on the crate?"
So, if we are going to calculate the resulting static friction force, it means that there is no movement, we must remember that the friction coefficient will give us the maximum force before the crate starts to move.
We can calculate the static friction force by using the following formula:

Since the crate is not moving (static), the static friction force acting on the crate will be equal to the applied force.
Calculating we have:


Hence, the static friction force is equal to 20 N to the left (since the applied force is acting to the right)
So,
Since the static friction force is equal to the applied force, the crate does not start to move.
Have a nice day!
Answer:
a)693.821N/m
b)17.5g
Explanation:
We the Period T we can find the constant k,
That is

squaring on both sides,

where,
M=hanging mass, m = spring mass,
k =spring constant
T =time period
a) So for the equation we can compare, that is,

the hanging mass M is x here, so comparing the equation we know that

b) In order to find the mass of the spring we make similar process, so comparing,
