Without air resistance,a projectile fired horizontally at 8 km/s from a mountain top will
A)accelerate downward at g as it moves horizontally.
B)trace a curve that matches Earth's curvature.
C)return to its starting position and repeat its falling behavior.
D)all the above
E)none of the above

Question

Quizplus · Accepted Answer

A projectile fired horizontally in the absence of air resistance will indeed accelerate downward at the acceleration due to gravity (g) because the only force acting on it is gravity. This causes it to trace a curve as it moves horizontally. If the projectile is fired at a speed of 8 km/s, which is close to Earth's orbital velocity, it will trace a curve that matches the Earth's curvature, effectively going into orbit if it doesn't encounter obstacles like mountains or the atmosphere. This means it would not return to its starting position on the mountain but would continue moving around the Earth, assuming it has achieved the necessary horizontal velocity for orbit and there are no other forces acting on it like air resistance.

Without Air Resistance,a Projectile Fired Horizontally at 8 Km/s from a Mountain