The force of the ruler on the ball is called an applied force. The force of the barrier on the ball is called a normal force. Both of these forces are exerted by surfaces, and the direction of force is at a right angle to the surface. The difference is that an applied force is exerted by a moving object and a normal force is exerted by a stationary object. Draw two arrows to represent the applied force and the normal force on the ball.

ammonium chloride & tallow

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.

not too sure thinking all accelerations are pointed down

this would be about 43%