1. NEWTON’S SECOND LAW OF MOTION Law of Acceleration

2. Newton’s 2 nd Law of Motion  The acceleration of an object is:  directly proportional to the net force acting on the object  in the direction of the net force  inversely related to the mass of the object.

3. Force – Acceleration Formula F = m·a F = force (N) m = mass (kg) a = acceleration (m/s 2 )

5. Examples of Problems 1. What net force is required to accelerate a 1500-kg race car at 3.00 m/s 2 ? 2. An artillery shell has a mass of 55 kg. The shell is fired from a gun with a force of 1.1 X10 7 N. What is the acceleration of the shell?

6. More Examples!! 3. When a shot-putter exerts a net force of 140 N on a shot, the shot has an acceleration of 19 m/s 2. What is the mass of the shot? 4. A 1225 kg car is traveling at 105 km/hr accelerates to 157 km/hr in 4.5 seconds. How much force was applied to the car from the engine?

7. Finding Distance from Acceleration Data:  If the initial speed, time and acceleration of the object are known, the distance the object travelled can be calculated. d = ½a·t 2 + v i ·t d = distance (m) a = acceleration (m/s 2 ) t = time (s) v i = initial speed (m/s)

8. Example of Problems 1. An object is accelerating from rest at a rate of 2.5 m/s 2 for 3.9 seconds. How far did the object travel?

9. Challenge Question: 2. A boy increases his velocity on a bike from 2.5 km/hr to 16.3 km/hr in 0.15 minutes. a. How many feet did the boy ride in those 0.15 minutes? b. How much force did the boy provide to accelerate his bike if the mass of the boy + bike is 95.4 kg?