Is b= acid + base - water + salt.
Answer:
Let d be the density of fluid.
So , Initial reading of balance, F1 =30dg N
After the level reaches 50cm^3
Final reading of balance , F2 =50dg N
Given that difference between final and initial reading is 30g
i.e, F2 −F1
=30 g
⟹50dg−30dg=30g
⟹20dg=30g
⟹d=30g/20g
⟹d=1.5g/cm^3
So, density of fluid is 1.5g/cm^3
To solve this problem it is necessary to apply the equations related to the conservation of momentum. Mathematically this can be expressed as

Where,
= Mass of each object
= Initial velocity of each object
= Final Velocity
Since the receiver's body is static for the initial velocity we have that the equation would become



Therefore the velocity right after catching the ball is 0.0975m/s
Answer:
The answer is β=0,85 rads
Explanation:
As the ladder is leaning against the building, we can imagine there´s a triangle where 20ft is the hypotenuse and 15ft is the maximum vertical distance between the ladder and the ground, it means, the leg opposite to β which is the angle we need
Let β(betha) be the angle between the ladder and the ground
We also know that 
In this case we will need to find β, this way:

Then β=48,6°
We also have that 2πrads is equal to 360°, in this way we find how much β is in radians:

then we find β=0,85rads