BMST Newton's Laws of Motion 2 — Questions and Answers
Question 1: A 10 kg box is pushed with a net force of 30 N. What is the acceleration of the box?
- 0.33 m/s²
- 3 m/s² (Correct answer)
- 300 m/s²
- 20 m/s²
Correct answer: 3 m/s²
Newton's second law: a = F/m = 30 N / 10 kg = 3 m/s².
Question 2: Which of Newton's laws explains why passengers lurch forward when a car suddenly brakes?
- Newton's Third Law
- Newton's Second Law
- Newton's First Law (Correct answer)
- Law of Gravitation
Correct answer: Newton's First Law
Newton's First Law states objects in motion stay in motion; passengers continue moving forward when the car stops.
Question 3: A rocket expels gas downward to propel itself upward. This is best explained by:
- Newton's First Law
- Newton's Second Law
- Newton's Third Law (Correct answer)
- The Law of Conservation of Energy
Correct answer: Newton's Third Law
Newton's Third Law: the rocket pushes gas down, and the gas pushes the rocket up with an equal and opposite force.
Question 4: If the mass of an object doubles while the net force stays the same, the acceleration will:
- Double
- Stay the same
- Quadruple
- Halve (Correct answer)
Correct answer: Halve
Since a = F/m, doubling mass with constant force cuts acceleration in half.
Question 5: An object sitting on a table remains at rest. According to Newton's First Law, this means:
- There are no forces acting on it
- The net force on it is zero (Correct answer)
- Gravity is not acting on it
- The table is pushing it upward with more force than gravity
Correct answer: The net force on it is zero
An object at rest has balanced (zero net) forces; gravity and the normal force cancel each other.
Question 6: Two ice skaters push off each other. Skater A has twice the mass of Skater B. Compared to Skater B, Skater A will have:
- Twice the acceleration
- The same acceleration
- Half the acceleration (Correct answer)
- Four times the acceleration
Correct answer: Half the acceleration
They experience equal forces (Third Law), but a = F/m means greater mass gives less acceleration.
Question 7: Which quantity is measured in Newtons (N)?
- Mass
- Acceleration
- Force (Correct answer)
- Velocity
Correct answer: Force
The Newton is the SI unit of force, defined as 1 kg·m/s².
BMST Newton's Laws of Motion 2
A 10 kg box is pushed with a net force of 30 N.
What is the acceleration of the box?