1. Newton’s 2nd Law of Motion
Define Newton’s second law of motion.
Apply Newton’s second law of motion.

2. Newton’s 2nd Law of Motion
The acceleration of an object depends on the mass of the object and the net force exerted on the object. Under the same force, a heavy object will not accelerate as fast a light object.
The acceleration of an object is in the direction of the net force on the object.
2,000 kg
.05 m/s/s
? N

3. Newton’s 2nd Law of Motion (cont.)
Sports Example:
When hitting a tennis ball, the force of the racquet swing causes the ball to accelerate in the direction of the swing force.
A heavier ball is slower than a lighter one.

4. Newton’s 2nd Law of Motion (cont.)
Equation: Force = Mass x Acceleration
(kg) (m/s2)
SI Unit: Newtons (N)
F = ma

5. Newton’s 2nd Law of Motion (cont.)
What is the net force on a dragster with a mass of 900 kg if its acceleration is 32.0 m/s2?
f =
m =
a =
F = ma
F = 900kg * 32 m/s/s = 28,800 N
F = ma

6. Newton’s 2nd Law of Motion (cont.)
What is the acceleration of an airplane that has the mass of 45,000 kg when an 180,000 N force is applied to it?
f =
m =
a =
F/m = a
180,000N/45,000kg = 4 m/s/s
F = ma

7. Newton’s 2nd Law of Motion (cont.)
A tugboat is helping a cargo ship into the dock. What is the cargo ship’s mass if the net force on the cargo ship is 6,000,000 N and it has an acceleration of 2.0 m/s2?
f = m =
a =
F/a = m
6,000,000N/2.0m/s/s = 3,000,000 kg
F = ma