Unit 5 Newton's Law of Motion CP Physics Review

What happens to an object when the net force acting on it is zero?

• a. It moves with constant velocity.

• b. It accelerates.

• c. Its mass increases.

• d. Its speed decreases gradually.

Answer explanation

When an unbalanced force acts on an object, the object accelerates due to the net force causing a change in its motion.

Tags

NGSS.HS-PS2-1

According to Newton's second law of motion, the acceleration of an object is directly proportional to the _____ and inversely proportional to its _____.

• a. net force, mass

• b. velocity, volume

• c. mass, net force

• d. gravity, area

Answer explanation

The correct choice is acceleration because according to Newton's second law, acceleration is directly proportional to the net force applied to an object.

Tags

NGSS.HS-PS2-1

An object with a mass of 20 kg is pushed with a force of 40 N. What is the acceleration of the object?

• a. 2 m/s²

• b. 8 m/s²

• c. 20 m/s²

• d. 0.5 m/s²

Answer explanation

The object's mass remains constant at 50 kg regardless of its acceleration or position, making mass the correct choice.

Tags

NGSS.HS-PS2-1

Which vector diagram accurately depicts an object in motion at constant velocity on a flat surface?

• 1

• 2

• 3

Answer explanation

Vector diagram 3 represents a cart in static equilibrium on a horizontal surface by showing balanced forces in all directions.

Which vector diagram correctly illustrates a cart accelerating to the left?

• 1

• 2

• 3

Answer explanation

Vector diagram 1 best represents a cart accelerating to the right on a horizontal surface as the arrow points in the direction of acceleration.

Tags

NGSS.HS-PS2-1

A car moving in a circular path at uniform speed has _____.

• a. its velocity constant.

• b. a net force acting towards the center of the circle.

• c. no acceleration acting on it.

Answer explanation

An object following a straight-line path at a constant speed has net force equaling zero acting on it.

Tags

NGSS.HS-PS2-1

What is the force required to maintain the velocity of an object moving in space, assuming no external forces?

• a. Equal to the force initially applied to set it in motion.

• b. Zero, because objects in motion remain in motion unless acted upon by an external force.

• c. Twice the initial force to overcome space resistance.

• d. It gradually increases as the object moves further into space.

Answer explanation

The correct answer is a. zero, since no force is necessary to keep it moving. In frictionless space, no force is needed to maintain the cannonball's motion.

Tags

NGSS.HS-PS2-1

What is the minimum resultant possible when adding a 3-N force to a 5-N force in the opposite direction?

• a. 2 N

• b. 3 N

• c. 5 N

• d. 8 N

Answer explanation

The maximum resultant when adding forces is the sum of the forces, so 2 N + 8 N = 10 N. Therefore, the correct answer is d. 10 N.

Tags

NGSS.HS-PS2-1

Newton's third law states that for every action, there is an equal and opposite _____.

• a. reaction.

• b. acceleration.

• c. force.

Answer explanation

According to Newton’s second law of motion, the acceleration of an object equals the net force acting on the object divided by the object’s mass, making choice a the correct answer.

Tags

NGSS.MS-PS2-1

Newton's third law states that for every action there is

• an equal and opposite reaction.

• a similar action in the same direction.

• no significant effect.

• a reaction that cancels the action.

Answer explanation

Forces always occur in triplets, according to Newton's third law of motion.