Newton's First Law of Motion

Newton's First Law of Motion

What is motion?

Motion is a change in position relative to a frame of reference.

Reference Point

• A place or object used for comparison to determine if something is in motion.

• Movement is relative to an object that appears stationary

• Earth is the most common frame of reference.

Open Ended

What is the frame of reference for the sunset?

Multiple Choice

Is a person who is seated on a moving train in motion in relation to the train?

• Yes

• No

Multiple Choice

Is the same train passenger in motion in relation to a tree outside of the train?

• Yes

• No

Speed

• Speed is the distance traveled in a given amount of time.

• Speed = distance/ time

• The units for speed: meters/second (m/sec), kilometers/hour (km/hr), or miles/hour (mph).

Speed= distance/ time

Velocity

• A quantity that describes the speed of the object and its direction of travel.

• The rate of change of an object's position in a reference frame.

• Constant velocity is always motion along a straight line.

• If an object moves in a positive direction, then we use a positive number to represent the velocity.

• If an object moves in a negative direction, then we use a negative number to represent the velocity.

Multiple Choice

A place or object used for comparison to determine if another object is in motion is called a

• comparison point

• reference point

• point of view

• motion detector

Multiple Choice

A runner races in the 100 meter dash. It takes her 10 seconds to finish. What is her average speed?

• 10 m/s

• 1000 m/s

• 100 seconds

• 10 seconds

Multiple Choice

What is the formula to calculate speed?

• S = t/d

• S = d/t

• S = d x t

• S = t x d

Multiple Choice

A change in an object's position is called ______.

• Speed
• Motion
• Velocity
• Friction

Open Ended

A bus travels north along a straight stretch of road. Its velocity is a constant 15 m/s. Another bus travels south on the same road at the same speed. What is the velocity of the second bus?

Multiple Choice

The measure of how fast an object is moving and what direction it is moving

• velocity

• force

• speed

• acceleration

Multiple Choice

What is this graph showing?

• Constant Speed
• Acceleration (speeding up)
• Deceleration (slowing down)
• No motion

Newton's First Law of Motion

Unless acted on by an unbalanced force, an object at rest stays at rest and an object in motion stays in motion at a constant velocity.

Inertia and Newton's First Law

• Another name for Newton's First Law

• Inertia is the tendency of objects to resist any change in motion.

• Objects with more mass have more inertia than objects with less mass.

• More force is needed to overcome the inertia of a massive object to change its motion than is needed to cause the same change in the motion of a less massive object.

Multiple Choice

If an object in motion is not acted on by an unbalanced force, it will continue with the same speed and direction.

• True

• False

Multiple Choice

An object's tendency to resist change in its state of motion.

• gravity

• force

• inertia

• friction

Multiple Choice

An object at rest will stay at rest unless an unbalanced force acts on it.

• True

• False

Poll

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