Answer: independent variable: Size of the feather.
Explanation:
In an experiment, the manipulated/independent variable is, as the name implies, the variable that the scientist can control.
In this case, the scientist has only one variable that he can control at will, and this is the size of the feather (he can choose which feather he uses for the experiment)
So the manipulated variable will be the size of the feather.
And the dependent variable is the one that "answers" to the changes in the manipulated variable.
In this case, will be the time that it takes to the feather to fall to the ground.
Answer:
The dentist uses X-ray radiography, which takes too short a time to cause those problems.
Explanation:
I took the test on Edg
Answer:
The final velocity of the cart is
Explanation:
From the question we are told that
The mass of the girl is 
The mass of the cart is 
The speed of the cart and kid(girl) is 
The final velocity of the girl is 
Let assume that velocity eastward is positive and velocity westward is negative (Note that if we assume vise versa it wouldn't affect the answer )
The total momentum of the system before she steps off the back of the cart
is mathematically evaluated as

substituting values


The total momentum after she steps off the back of the cart is mathematically evaluated as

Where
is the final velocity of the cart
substituting values


Now according to the law of conservation of momentum

So

=> 
Since the value is positive it implies that the cart moved eastward