EmSAT Physics Flashcards

What is Newton's second law of motion?

Answer: F = ma

Newton's second law states that force equals mass times acceleration: F = ma. It describes how the motion of an object changes when a net force acts on it.

A car travels 120 km in 2 hours. What is its average speed?

Answer: 60 km/h

Average speed = distance ÷ time = 120 km ÷ 2 h = 60 km/h.

What is the unit of force in the SI system?

Answer: Newton

The SI unit of force is the Newton (N), defined as the force needed to accelerate a 1 kg mass at 1 m/s². It is named after Isaac Newton.

An object is in free fall. What is its acceleration? (ignore air resistance)

Answer: 9.8 m/s²

On Earth, the acceleration due to gravity is approximately 9.8 m/s² downward. All objects in free fall (ignoring air resistance) accelerate at this rate.

What does the area under a velocity-time graph represent?

Answer: Distance

The area under a velocity-time graph represents the displacement (distance traveled). This is derived from the relationship: distance = velocity × time.

Which of Newton's laws explains why a seat belt protects you in a crash?

Answer: First law (inertia)

Newton's first law states that objects in motion stay in motion unless acted upon by a net force. In a crash, your body continues moving forward due to inertia; the seat belt provides the force to stop you.