Answer:
Explanation:
Remark
This is a second class lever. It is much more efficient than the fishing pole problem. All distances are measured from the pivot in these kinds of questions.
Givens
d1 = 1.5
d2 = ?
m1 = 50 kg
m2 = 30 kg
The lighter child will have to sit further away from the pivot to make the two conditions equal.
Formula
d1*m1 = d2*m2
1.5*50 = d2 * 30
75 = 30 * d2
75/30 = d2
d2 = 2.5
Remark
Notice that the distance is longer for the lighter child. The fact that these are masses and not forces does not matter, but you should take note of it. There is a difference between masses and forces. See the fishing pole problem.
Answer to the multiple Choice question. No motion on this kind of problem means equal moments. The answer is D
Problem 2
1) The wheels are further apart making B more stable. The wider the distance the wheels are apart, the harder it would be to tip the concrete mixer over
2) The center of gravity is lower. The higher the force is the more chance you have of exerting an external force to tip the mixer over.
Answer:

Explanation:
From the law of conservation of energy
Energy lost by the spring, W=Kinetic energy gained, KE+Potential energy gained, PE+Work done by friction, Fr



The required distance from A to B is 
Answer:
<em><u>172,000 second </u></em>
<em><u>I'M</u></em><em><u> </u></em><em><u>NOT</u></em><em><u> </u></em><em><u>SURE</u></em><em><u> </u></em><em><u>THAT</u></em><em><u> </u></em><em><u>THIS</u></em><em><u> </u></em><em><u>IS</u></em><em><u> </u></em><em><u>RIGHT</u></em><em><u> </u></em><em><u>OR</u></em><em><u> </u></em><em><u>WRONG</u></em><em><u> </u></em><em><u> </u></em><em><u>IF</u></em><em><u> </u></em><em><u>IT'S</u></em><em><u> </u></em><em><u>WRONG</u></em><em><u> </u></em><em><u>THEN</u></em><em><u> </u></em><em><u>SORRY</u></em><em><u> </u></em>
The answer is true
<span>Nuclear Fusion is 2 small nuclei to form one that's bigger</span>