Given two questions:
<span>1) If a car passes a pedestrian, a change in pitch is ______________.
The answer is the change in pitch is perceived by the pedestrian since he is the one in a relatively constant position compared to the car passing.
2) </span><span>In the Doppler Effect lab, which statement best describes what you demonstrated about speed and pitch?
The answer is 'speed and direction affect pitch'.</span>
The mass of a 0.513 mol of Al2O3 is 52.33g.
HOW TO CALCULATE MASS:
The mass of a substance can be calculated by multiplying the molar mass of the substance by its number of moles. That is;
mass of Al2O3 = no. of moles of Al2O3 × molar mass of Al2O3
According to this question, there are 0.513 moles of Al2O3.
Mass of Al2O3 = 0.513 × 102
Mass of Al2O3 = 52.33g
Therefore, the mass of a 0.513 mol of Al2O3 is 52.33g.
Learn more about mass calculations at: brainly.com/question/8101390?referrer=searchResults
Answer: The momentum of the child and milk together is 58.125 kg.m/s
Explanation:
Momentum is defined as the product of object's mass and velocity.
Mathematically,

where, p = momentum
m = mass of the object
v = velocity of the object
In the given question, we are given that a child of mass 21.0 kg is carrying a gallon of milk having mass 2.25 kg and running with a velocity of 2.5 m/s. Hence, the momentum by both milk and child will be:
....(1)
Given:

Putting values in equation 1, we get:

Hence, the momentum of the child and milk together is 58.125 kg.m/s
Answer:5-3=2
As 5apple eaten 3apple so left 2apple