Answer:
C
Explanation:
Without thinking, the answer is C.
The problem is with D. Of course it is going to depend on the transparency. If the material is a rock, then the light won't go through, and n >>>1. I don't think you are intended to think that way, but I sure wish D wasn't there. I'd answer C, but be prepared to see it come out as D.
If you are trying to find for the final velocity of the two boys, consider that the collision that has occurred is a perfect inelastic collision because they hung on to each other, meaning they moved together as one. This can be solved using the formula:
m1 = mass of object 1
m2 = mass of object 2
v1i = velocity of object 1 before the collision
v2i = velocity of object 2 before the collision
vf = final velocity
Now based on your problem the given would be the following:
m1 = 45kg (Mass of Jacob)
m2 = 31 kg (Mass of Ethan)
v1i = 7.81 m/s (Jacob)
v2i = -10 m/s (Ethan) (Now this is negative because he is coming from the opposite direction.)
Now all you need to do is input the given by filling in what you know and solving for what you don't know.
Transpose the 76kg to the other side of the equation to isolate vf.
Because the value is positive, that means it is following the direction Jacob was going. So the final velocity is
0.545m/s to the right.
Answer:
E = 301.5 J
Explanation:
We have,
Mass of mother, m = 67 kg
Here, a sneaky teenager crawls under the trampoline and uses the ring to pull the trampoline slowly down. As she passes through the position at which she was before her son stretched the trampoline, her speed is 3 m/s.
It is required to find the elastic potential energy the son add to the trampoline by pulling it down. It is based on the conservation of energy.
The elastic potential energy of the mother = the elastic potential energy the son add to the trampoline.
So, the elastic potential energy is :
So, the elastic potential energy of 301.5 J the son add to the trampoline by pulling it down.