Newton’s Laws of Motion

Definition: An object at rest remains at rest and an object in motion maintains its positionunless it experiences an Outside force.

Newton’s 1st Law

Inertia is the tendency of an object at rest to remain at rest or, if moving, to continue moving with a constant velocity.

All objects have inertia because they resist changes in motion.

The greater the massof the object the more force required to change it’s motion.

Newton’s 1st Law

Why should infants be placed in special-

backward facing car seats?

Concept Check 1

Definition: The unbalanced force acting on an object

equals the object’s mass times its acceleration.

Mathematically represented by the equation:Force= mass x acceleration or F=ma

Cenzo was here

Remember the SI unit for force is a Newton

Newton= 1 kg x m/s2 towards center of the earth

Newton 2nd Law

Definition: the motion of a body when only the

force of gravity is acting on it

Acceleration near the Earth’s surface is constant.

All objects on Earth accelerate at exactly 9.8 m/sec/sec.

Gravity is abbreviated as g

Free Fall

In the absence of air resistance which will hit

the ground first?

Concept Check 2

Definition: The force on an object due to

gravity is called its weight

1 Newton= 1 kg x m/s2 towards center of the earth= 0.22481 lbs or pounds

Weight

Astronauts and their surroundings all

accelerate at the same rate. Consequently, the floor of the shuttle pushes up against the

astronauts or objects in the shuttle.

Apparent Weightlessness

Definition: the terminal velocity reached by a falling

object whose acceleration is zero. The terminal velocity of a falling body occurs during free fall when a falling body experiences zero acceleration. This is because of the retarding force known as air resistance. Air resistance exists because air molecules collide into a falling body creating an upward force opposite gravity. This upward force will eventually balance the falling body's weight. It will continue to fall at constant velocity known as the terminal velocity.

http://hypertextbook.com/facts/JianHuang.shtml

Terminal Velocity

1. What is the net force necessary for a 3.6 x

103 kg truck to accelerate forward at 2.0 m/s2.

2. A baseball accelerates downward at 9.8 m/s2. If the gravitational force acting on the baseball is 1.8 N, what is the baseball’s mass?

3. A bobsled and crew have a combined mass of 525 kg. If the bobsled experiences an unbalanced force of 1095 N pushing it forward, what is the bobsled’s acceleration?

Newton’s Second Law Math Problems

For every action force, there is an equal and

opposite reaction force.

Applies force always acts in pairs _.

Principle used in rocketry.

Newton’s 3rd Law

1. Why won’t the elephant move?

2. What is the difference between weight and mass?

3. If the elephant has a mass of2000 Kg and the person is pushingat 60 N what is the accelerationof the elephant?

End Check- complete on a separate sheet

4. State each of Newton’s three laws of motion in

your own words and give an example that demonstrate each law

5. Explain the difference between mass and weight. Does the weight of an object ever change? If so, when?

6. Using Newton’s laws, predict what will happen when a car traveling on a icy roada. Comes to a sharp bendb. Has to stop quickly

7. How much does a 7.0 kg puppy weigh on Earth?

End Check- complete on a separate sheet