9. Momentum & Newton's 1st Law

Question 1

What is Newton’s First Law?

Answer 1

Newton’s First Law states that an object at rest will remain at rest, and an object in motion will continue in motion with the same speed and in the same direction unless acted upon by a net external force.

Question 2

Newton’s First Law

What is the Law of Inertia?

Answer 2

Every body remains in a state of constant velocity
unless acted upon by an external force

• A system at rest remains at rest
• A system moves in a uniform manner

Question 3

What is Inertia?

Answer 3

A tendency to remian unchanged

The amount of inertia in a system is proportional to its mass

Question 4

How does a systems mass affect inertia?

Answer 4

Heavier objects are more resistant to change,
harder to move

Lighter objects are less resistant to change,
easier to move

Question 5

According to Newton’s 1st Law, is it possible to blow your own sail?

Answer 5

No, Internal force are not enough to create movement

Question 6

When an object is in motion it has momentum.
What is momentum?

Answer 6

• Momentum is the quantity of motion
• The strength/force that a system has when its moving
• Momentum (M) = mass (m) x velocity (v)
• Units: Kg*m/s

Question 7

How is momentum related to Newtons 1st Law?

Answer 7

According to Newton’s 1st Law, in the abscence of an external force, every system remains in a constant state of motion

So the momentum in one instance should be the same as the momentum in another instance:

• M1=M2
• Conservation of Momentum

Question 8

In this case, The momentum (velocity) of the stick is transferred to the puck. How can we maximize the transferred momentum?

Answer 8

• Swing the stick faster to increase velocity
• Use a heavier stick to hit the puck
• Find best combination of the two