# Rate of change of surface area of sphere

**Problem**

Gas is escaping from a spherical balloon at the rate of 2 cm^{3}/min. Find the rate at which the surface area is decreasing, in cm^{2}/min, when the radius is 8 cm..

# 01 Minimum length of cables linking to one point

# Deflections Determined by Three-Moment Equation

# Angle between two chords

# Problem 01 - Equation of a curve

# 02 - Bullet fired from the top of a building

**Problem 02**

A bullet is fired at an initial velocity of 150 m/s and an angle of 56° at the top of a 120 m tall building. Neglecting air resistance, determine the following:

- The maximum height above the level ground that can be reached by the bullet.
- The time for the bullet to hit the ground.
- The velocity with which the bullet will hit the ground.

# The Moment Distribution Method

Moment distribution is based on the method of successive approximation developed by Hardy Cross (1885–1959) in his stay at the University of Illinois at Urbana-Champaign (UIUC). This method is applicable to all types of rigid frame analysis.