The metric (SI) unit of mass is the **<em>kilogram</em>**.

On Earth, 1 kilogram of mass weighs about 2.205 pounds.

**Answer:**

The depth and acceleration are 0.1919291 ft and 3.61 m/s².

**Explanation:**

**Given that,**

Density of block

Density of fluid

**We need to calculate the depth**

**Using balance equation**

....(I)

We know that,

The density is

Put the value of m in equation (I)

Put the value into the formula

**We need to calculate the acceleration**

**Using formula of net force**

....(II)

Put the value in the equation (II)

**Hence, The depth and acceleration are 0.1919291 ft and 3.61 m/s².**

**Answer:**

**f = 735 Hz**

**Explanation:**

given,

Person distance from speakers

r₁ = 4.1 m r₂ = 4.8 m

Path difference

d = r₂ - r₁ = 4.8 - 4.1 = 0.7 m

For destructive interference

where, n = 1, 3,5..

we know, λ = v/f

v is the speed of the sound = 343 m/s

f is the frequency

for n = 1

f = 245 Hz

for n = 3

**f = 735 Hz**

Hence**,the second lowest frequency of the destructive interference is 735 Hz.**