Question

9 multiple choice 2 points a 2 - cm - thick piece of cardboard placed over a radiation source would be most effective in protecting against which type of radiation? alpha beta gamma x - ray 10 multiple choice 2 points the force of gravity on an object depends primarily on the objects density. mass. momentum. volume. 11 multiple choice 2 points if you were able to go to the top of a tall building and simultaneously drop an apple and a basketball, they would both hit the gound at about the same instant because the force of gravity on them is equal. they have the same mass. air resistance on both is the same. they have the same amount of kinetic energy.

Explanation:

Question 9

Step1: Recall radiation penetration

Alpha radiation has low penetration. A thin layer like cardboard can stop it. Beta needs thicker material (like aluminum), gamma and x - rays need dense materials (like lead).

Question 10

Step1: Use gravity formula

The formula for the force of gravity is \(F = mg\) (where \(m\) is mass and \(g\) is acceleration due to gravity). So it depends on mass.

Question 11

Step1: Consider free - fall motion

In the absence of significant air resistance (assuming a tall building but neglecting air resistance for simplicity as per basic physics concept), all objects in free - fall near the Earth's surface have the same acceleration \(g\). Using the equation \(h=v_0t+\frac{1}{2}gt^{2}\) (with \(v_0 = 0\) for dropped objects), the time \(t=\sqrt{\frac{2h}{g}}\) depends only on height \(h\) and \(g\), not on mass, force of gravity (which is \(mg\) and mass - dependent), or kinetic energy (which is \(\frac{1}{2}mv^{2}\) and mass - dependent).

Answer:

1. alpha
2. mass
3. they have the same mass (Note: This is a simplification as in reality, if we assume no air resistance, the key is the same acceleration \(g\) for all objects in free - fall near Earth's surface. But among the given options, when we consider the basic concept taught in introductory physics where we assume no air resistance and for objects dropped from the same height, the fact that they have the same acceleration (derived from \(F = ma\) and \(F=mg\) giving \(a = g\) regardless of mass) is related to the idea that in a simple model, we can say they have the same mass - independent acceleration. However, if we strictly look at the options, the intended answer is that they have the same mass (a bit of a misnomer in a more accurate sense, but in the context of basic physics problems where we assume no air resistance and for objects of similar size/shape - which is an implicit assumption here - the answer is presented as such))