Chapter 14, Problem 15A

Neglecting air resistance, what will happen to a projectile that is fired vertically at 8 km/s? At 12 km/s?

To determine

The condition of projectile if it fired vertically at given speeds.

Answer to Problem 15A

When initial speed of a projectile is 8 km/s, then it will come back to the Earth’s surface.

When initial speed of a projectile is 12 km/s, then it will escape.

Explanation of Solution

Introduction:

Escape velocity is the minimum velocity that is required to escape an object from the influence of Earth’s gravitational of Earth.

The escape velocity of an object is 11.186 km/s from the Earth’s surface. Consider the case when initial velocity is 8 km/s. Since the initial velocity is less than the escape velocity of Earth, so an object will go up to a maximum height at which velocity becomes zero and then comes back to the ground.

Consider the case when initial velocity is 12 km/s. Since the initial velocity is greater than the escape velocity of Earth, so an object will escape from the Earth’s gravitation influence.