Question

One stone is projected horizontally from a 20 m high cliff with an initial speed of 10ms⁻¹. A second stone is simultaneously dropped from that cliff.Which of the following is true?

A. Both strike the ground with the same velocity
B. The ball with initial speed 10ms⁻¹ reaches the ground first
C. Both the balls hit the ground at the same time
D. One cannot say without knowing the height of the building

Answer 1

Option c is the correct answer. In projectile motion, ignoring air resistance, objects dropped from the same height will hit the ground at the same time regardless of their horizontal velocity, because vertical motion is independent of horizontal motion.

Step-by-step explanation:

The question concerns the subject of physics, specifically within the area known as projectile motion. According to the principles of physics, ignoring air resistance, the time it takes for an object to fall is determined solely by the height from which it falls and the acceleration due to gravity, which is approximately 9.81 m/s2 on Earth. Therefore, whether a ball is dropped from rest or projected horizontally with some initial speed, both will hit the ground at the same time because vertical motion is independent of horizontal motion. The correct answer to the given problem is C. Both the balls hit the ground at the same time.