PH 03 TB Forces and Newton's Laws

What is the resistance of an object to changes in its motion called?

• Force

• Inertia

• Friction

• Tension

Answer explanation

The resistance of an object to changes in its motion is called inertia. It describes how much an object resists acceleration when a force is applied, making 'inertia' the correct answer.

Explain Newton's Third Law of Motion.

Answer explanation

Newton's Third Law of Motion states that for every action, there is an equal and opposite reaction. This means that forces always occur in pairs; when one object exerts a force on another, the second object exerts a force of equal magnitude in the opposite direction.

Tags

NGSS.MS-PS2-1

Fill in the blank: The force that acts between moving materials is called ________.

Answer explanation

The force that acts between moving materials is called friction. It opposes the relative motion of surfaces in contact, making it the correct term to fill in the blank.

Match the following terms with their definitions: Inertia, Normal Force, Tension, Friction.

• Friction

• contact force that is perpendicular to the surface and opposite to the weight of an object

• Normal Force

• Force in a wire or string

• Inertia

• Force between moving materials

• Tension

• Resistance to change in motion

Newton's First Law is also known as the law of (a)   .

• Motion

• Inertia

• Gravity

• Friction

Answer explanation

Newton's First Law states that an object at rest stays at rest and an object in motion stays in motion unless acted upon by a force. This principle is known as the law of Inertia, highlighting the tendency of objects to resist changes in their state.

Where is the normal force acting on an object on a ramp?

• Perpendicular to the ramp

• Parallel to the ramp

• Opposite to gravity

• Along the ramp

Answer explanation

The normal force acts perpendicular to the surface of the ramp. This force counteracts the component of gravity acting on the object, ensuring it does not accelerate through the ramp.

Tags

NGSS.HS-PS2-1

Explain how tension in a string is affected when the string is angled.

Answer explanation

When a string is angled, the tension increases due to the component of the weight acting along the string. The greater the angle, the more tension is required to maintain equilibrium, as the vertical component of the tension must balance the weight.

Tags

NGSS.HS-PS2-1

The coefficient of static friction is always _______ than the coefficient of kinetic friction.

Answer explanation

The coefficient of static friction is always greater than the coefficient of kinetic friction. Static friction prevents motion, while kinetic friction occurs during motion, making static friction typically higher.

Gravity can be decomposed into its x- and y-components relative to the ramp. Which of the following represents the y-component?

• Fg cos θ

• Fg sin θ

• Fg tan θ

• Fg

Answer explanation

The y-component of gravity on a ramp is found using the cosine function. It represents the force acting perpendicular to the ramp's surface, calculated as Fg cos θ, where Fg is the gravitational force and θ is the ramp angle.

Tags

NGSS.HS-PS2-4

What is the formula for force according to Newton's second law?

• F = ma

• F = μN

• F = mg

• F = mgh

Answer explanation

According to Newton's second law, the formula for force is F = ma, where F is force, m is mass, and a is acceleration. This relationship shows how force is directly proportional to the mass and acceleration of an object.

Tags

NGSS.HS-PS2-1