Question

Describe the experiment of Galileo and what conclusion can be drawn from that experiment.

Answer 1

Step 1: Galileo used a ball and a ramp to begin the experiment by rolling the ball down the ramp.

1. When the ball is released from point $P$, Galileo observed that it rolls down the inclined plane $AB$ with increasing speed.
2. The ball keeps rolling at the same speed during $BC$.
3. The ball then rolls up the inclined plane $CD$ with decreasing speed and comes to instantaneous rest at $Q$.
4. He observed that the ball reaches nearly the same height $h$ from the ground.

Step 2: Now, Galileo decreases the inclination of $CD$.

1. Again, he releases the ball from point $P$ and observes that when the ball comes instantaneously at rest on plane $CD$ at point $Q$, the ball is nearly at the same height $h$ from the ground.
2. However, the distance travelled on plane $CD$ increases.
3. Galileo concluded that the body in these conditions had the tendency to reach the same height.

Step 3: Now, he decreases the inclination of $CD$ to zero.

1. Again, he releases the ball from point $P$ and observes that the speed of the ball goes on increasing down the incline till $B$.
2. Thereafter, it continues with the same speed in the horizontal direction.
3. If no force is applied to the ball then, it remains in its motion in the horizontal direction with the same speed.

From this observation, Galileo concluded that for continuous motion in a horizontal plane, no force is required.

Conclusions are drawn from the experiment:

1. In the absence of external forces, a body moving at a specific speed along a straight line path will continue to proceed at the same speed along the same straight-line path.
2. In practice, the bodies come to a halt due to friction, which always acts in the opposite direction of motion.