Lesson 2: Newton's Laws

Question 1

What is inertia?

Answer 1

• The tendency of objects continue in their state of rest or uniform motion is called inertia.

Question 2

What is Newton’s First Law?

Answer 2

• If the resultant force acting on an object is 0 AND:
• The object is stationary: the object remains stationary.
  OR.
• The object is moving, the object will continue to move at the same velocity (speed and direction.)

Question 3

When would the velocity of a moving object change?

Answer 3

• The velocity of a moving object will only change if there is a resultant force acting on the object.

Question 4

What is Newton’s second law?

Answer 4

• The acceleration of an object is proportional to the resultant force acting on the object and inversely proportional to the mass of the object.

Question 5

What is the equation that links resultant force, mass and acceleration?

Answer 5

• F=ma.

Question 6

What is inertial mass?

Answer 6

• Inertial mass is a measure of how difficult it is to change the velocity of an object.
• Inertial mass if defined as the ratio of force over acceleration.

Question 7

What speed do cars travel at on a main road vs on a motor-way?
What is the typical acceleration from main road to motor-way?

Answer 7

• Main road: 13m/s
• Motor- way: 30m/s
• Typical acceleration = 2m/s2
• That would require a force of 2000N for a typical car!!

Question 8

What is Newton’s third law?

Answer 8

• Whenever two objects interact, the forces they exert on each other are equal and opposite.