ST 2 Physical Science Review 2

When Scarlett applies the brakes on her bicycle, what happens to the bicycle?

• It speeds up

• It changes direction

• It slows down

• It maintains a constant velocity

Answer explanation

When Scarlett applies the brakes, friction is created, which reduces the bicycle's speed. Therefore, the correct answer is that the bicycle slows down.

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NGSS.MS-PS2-2

NGSS.MS-PS3-5

Hannah is observing different vehicles. Which of the following scenarios demonstrates zero acceleration?

• A car going around a curve at a constant speed

• A stationary car

• A ball falling to the ground

• A rocket launching upward

Answer explanation

A stationary car demonstrates zero acceleration because it is not changing its velocity. In contrast, the other scenarios involve changes in speed or direction, indicating acceleration.

Abigail is pushing a box across the floor, and the net force acting on the box is zero. The acceleration of the box is…

• Positive

• Negative

• Zero

• Infinite

Answer explanation

Since the net force acting on the box is zero, according to Newton's first law, the acceleration of the box must also be zero. Therefore, the correct answer is zero.

Abigail is driving her car and notices that it has an acceleration of -3 m/s². What does this mean?

• The car is speeding up.

• The car is slowing down.

• The car is moving at a constant velocity.

• The car is not moving.

Answer explanation

An acceleration of -3 m/s² indicates that the car is experiencing a decrease in speed. Therefore, the correct interpretation is that the car is slowing down.

During a bumper car ride at the amusement park, Aiden and Isla's cars collide and stick together. In this inelastic collision...

• Kinetic energy is conserved

• Momentum is not conserved

• Objects stick together after the collision

• The objects bounce off without losing energy

Answer explanation

In an inelastic collision, like Aiden and Isla's bumper cars, the objects stick together after the collision. This means they move as one combined mass, which is characteristic of inelastic collisions.

Tags

NGSS.MS-PS3-1

NGSS.MS-PS3-5

Which of the following is an example of an elastic collision?

• Two cars crashing and becoming entangled

• A tennis ball bouncing off a wall without losing speed

Answer explanation

An elastic collision is one where kinetic energy is conserved. A tennis ball bouncing off a wall without losing speed exemplifies this, as it retains its energy. In contrast, two cars crashing and becoming entangled is inelastic.

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NGSS.MS-PS2-1

NGSS.MS-PS3-1

NGSS.MS-PS3-5

During a car accident involving Henry and Mason, what is always conserved?

• Momentum

• Kinetic energy

• Speed

• Force

Answer explanation

In a car accident, momentum is always conserved due to the law of conservation of momentum. This means that the total momentum before the collision equals the total momentum after the collision, regardless of the forces involved.

Tags

NGSS.HS-PS2-2

Harper and Aria are playing with toy cars. They collide the cars on a track, and the cars stick together after the collision. Which of the following statements is true about this inelastic collision?

• Kinetic energy and momentum are both conserved

• Only momentum is conserved

• Neither momentum nor kinetic energy is conserved

• Objects always move at the same speed after the collision

Answer explanation

In an inelastic collision, momentum is conserved while kinetic energy is not. The cars stick together, meaning they move as one mass after the collision, confirming that only momentum is conserved.

Tags

NGSS.MS-PS3-5

Michael and Mason are playing with toy cars. They push their cars towards each other on a track. Which of the following describes what happens if the cars stick together after colliding?

• The cars stick together after the collision, and maximum kinetic energy is lost

• The cars bounce off each other with no loss of kinetic energy

• The cars remain stationary after the collision

• The collision results in an increase in kinetic energy

Answer explanation

When the cars stick together after colliding, they undergo a perfectly inelastic collision, resulting in maximum kinetic energy loss as some energy is transformed into other forms, like heat and sound.

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NGSS.MS-PS3-5

Zoe and Noah are driving two identical cars that collide and stick together after the collision. What type of collision is this?

• Elastic collision

• Inelastic collision

• Perfectly elastic collision

• Superelastic collision

Answer explanation

The collision between Zoe and Noah's cars is an inelastic collision because they stick together after the impact, indicating that kinetic energy is not conserved, while momentum is.

Tags

NGSS.HS-PS2-2