Newton's First and Second Laws

Question 1

What does Newton’s First Law state?

Answer 1

• If the resultant force on a stationary object is zero, the object will remain stationary.
• If the resultant force on a moving object is zero, it will carry on moving at the same velocity.

Question 2

When will acceleration or deceleration be produced?

Answer 2

A non-zero resultant force will always produce acceleration or deceleration in the direction of force.

Question 3

What is the resultant force proportional to?

Answer 3

The resultant force is directly proportional to the acceleration.
The bigger the resultant force, the more the object accelerates.

Question 4

What is acceleration inversely proportional to?

Answer 4

Acceleration is inversely proportional to mass.

The larger the mass, the less the object will accelerate.

Question 5

What is the formula for Newton’s Second Law?

Answer 5

F = ma

Resultant force (N) = mass (kg) x acceleration (m/s²)

Question 6

What three safety features in vehicles increase collision times?

Answer 6

• Crumple zones
• Air bags
• Seat belts

Question 7

What does Newton’s Second Law state?

Answer 7

Acceleration is proportional to the resultant force.

Question 8

Why are large decelerations dangerous?

Answer 8

They can cause serious injuries, as they require a large force.

Question 9

What happens on a vehicle’s wheels as it brakes?

Answer 9

• The brakes do work on the vehicle’s wheels.

- This transfers energy from the vehicle’s kinetic energy store to the thermal energy store of the brakes.

Question 10

What are the two disadvantages of a vehicle’s brakes during a large deceleration?

Answer 10

• Very large decelerations may cause the brakes to overheat, so they don’t work as well.
• They could also cause the vehicle to skid.