Answer:
Counterclockwise
Explanation:
We need to calculate the clocwkise and the counterclockwise torque.
The clockwise torque is the one generated by the child sitting on the right. This torque is given by:

where
is the force exerted by the child (his weight)
d = 1.8 m is the distance from the pivot point
So, the clockwise torque is

The counterclockwise torque is the one generated by the adult pushing on the left, and it is given by

where
F = 151 N is the force applied
d = 3.0 m is the distance from the pivot
Substituting,

So, the net torque is

And since the counterclockwise momentum is greater than the clockwise one, the teeter-totter will rotate counterclockwise.
Answer:
The dart with the small mass will travel the farthest distance.
Explanation:
Acceleration is proportional to force times mass, and inertia is proportional to mass. Inertia is the reluctance of a moving body to stop, and a stationary body to start moving (inertia increses with mass). Assuming they both have the same aerodynamic design, and that they are both launched with the same force applied for the same time duration, the dart with less small mass will accelerate faster than the big mass dart. From this we can see that the small dart will have covered a longer distance before the effect of the force stops, when compared to the more massive dart.
It's B-<span>Electromagnetic forces are stronger than gravitational forces</span>