Physics Chapter on Free Fall

Initial Conditions

• A steel ball is dropped from a height of 100 meters.
• The initial velocity is zero (0 m/s) as it's dropped, not thrown.
• After one second, the velocity of the ball is 10 m/s.

Acceleration Due to Gravity

• The ball accelerates downwards due to gravity.
• The acceleration due to gravity is approximately 9.8 m/s².
• This means the velocity of the ball increases by 9.8 m/s every second.

Velocity Calculation after One Second

• The velocity after one second (10 m/s) can be calculated using the equation: v = u + at, where:
  • v = final velocity
  • u = initial velocity
  • a = acceleration
  • t = time
• If u=0 m/s, a = 9.8 m/s², and t = 1 s, then v = 0 + (9.8 * 1) = 9.8 m/s
• The given value of 10 m/s is likely an approximation.

Velocity Calculation after Two Seconds

• To find the velocity after two seconds (t = 2 seconds), use the same formula:
  • v = u + at
    • Where:
      • u = initial velocity (0 m/s)
      • a = acceleration due to gravity (approximately 9.8 m/s²)
      • t = time (2 seconds)
• v = 0 + (9.8 * 2) = 19.6 m/s
• Therefore, the velocity of the ball after two seconds will be approximately 19.6 m/s.

Important Considerations

• Air resistance is ignored in this calculation. In reality, air resistance would slightly reduce the acceleration and final velocity.
• The value of acceleration due to gravity (9.8 m/s²) is an approximation; it can vary slightly depending on location. This is important for more precise calculations.
• The given velocity after one second (10 m/s) might be an approximation rounded from the more accurate value (9.8 m/s).