Review: Newton's 1st and 2nd Law

A force is:

• unabalaced

• balanced

• a push or pull

• an invisible quantity

Answer explanation

A force is defined as a push or pull acting on an object. This definition highlights the fundamental nature of force in physics, distinguishing it from concepts like balanced or unbalanced forces.

What is the SI unit for Force?

• Kilograms

• meters/second

• neutrons

• Newtons

Answer explanation

The SI unit for Force is Newtons, named after Sir Isaac Newton. It is defined as the force required to accelerate a one-kilogram mass by one meter per second squared. Other options do not represent force units.

What is the definition of a net force?

• A push only, not a pull

• The combined effect of multiple forces acting on an object

• A force that only causes movement

• A force that only works in one direction

Answer explanation

The net force is defined as the combined effect of multiple forces acting on an object. It determines the object's motion, taking into account both pushes and pulls, rather than being limited to just one type of force.

In a game of tug of war, when will neither team win?

• When Team A pulls harder than Team B

• When Team B pulls harder than Team A

• When the rope is perfectly straight

• When both teams exert equal and opposite forces

Answer explanation

Neither team wins when both teams exert equal and opposite forces, resulting in a balanced situation where no team can gain an advantage.

Which of the following statements best describes inertia?

• The tendency of an object to resist changes in its state of motion.

• The tendency of an object to remain in motion unless acted upon by a force.

• The force that opposes the motion of objects sliding past each other.

• The mass of an object multiplied by its acceleration.

Answer explanation

Inertia is best described as the tendency of an object to resist changes in its state of motion. This means that an object will remain at rest or in uniform motion unless acted upon by an external force.

How does inertia relate to an object's mass?

• Smaller objects have more inertia than larger ones

• Mass and inertia have no relationship

• The greater the mass, the greater the inertia

• Inertia only affects moving objects

Answer explanation

Inertia is the resistance of an object to changes in its state of motion. The greater the mass of an object, the greater its inertia, meaning it requires more force to change its motion. Thus, the correct answer is that the greater the mass, the greater the inertia.

According to Newton's First Law, why do objects in motion eventually stop?

• Because all moving objects naturally want to stop

• Because of outside forces like friction

• Because of gravity only

• Because objects prefer to be at rest

Answer explanation

According to Newton's First Law, objects in motion stop due to outside forces like friction, which oppose their motion. Without these forces, an object would continue moving indefinitely.

When a car makes a sudden stop, passengers move forward because:

• The car pushes them forward

• Their bodies want to keep moving at the same speed

• The seatbelt pulls them forward

• Gravity pulls them forward

Answer explanation

When a car suddenly stops, passengers continue moving forward due to inertia. Their bodies want to maintain the same speed they were traveling, which is why they lurch forward despite the car stopping.

View the image and determine which direction the object will move.

• Up

• Down

• Left

• Right

Answer explanation

The object is moving to the right because the visual cues in the image indicate a rightward trajectory, confirming that the correct answer is 'Right'.

View the image and determine which direction the object will move.

• Up

• Down

• Left

• Right

Answer explanation

The object is positioned above the reference point and will move downward due to gravity or the force applied, making 'Down' the correct choice.