Unit 5 S8P3- Force and Motion Assessment Prep

The diagram shows two girls pushing on a box with equal and opposite forces. Which statement BEST describes the forces required to move the box to the right?

• The forces must be balanced with the force from the left greater than the force from the right.

• The forces must be balanced with the force from the right greater than the force from the left.

• The forces must be unbalanced with the force from the left greater than the force from the right.

• The forces must be unbalanced with the force from the right greater than the force from the left.

Answer explanation

To move the box to the right, the force from the left must be greater than the force from the right, creating an unbalanced force. This allows the box to accelerate in the direction of the greater force.

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2

Which of the following can cause a moving object to change direction?

• acceleration

• velocity

• inertia

• force

Answer explanation

A moving object changes direction when a force is applied to it. While acceleration and velocity describe motion, it is the force that causes the change in direction, overcoming inertia.

Tags

NGSS.MS-PS2-2

NGSS.MS-PS2-5

Javier made a mistake on his list. Which best describes the mistake Javier made?

• A. Javier forgot to add that forces can never change.

• B. Balanced forces only cause objects to change directions.

• C. Unbalanced forces only cause objects to stay in the same place.

• D. Javier switched the descriptions for unbalanced and balanced forces.

Answer explanation

Javier's mistake was switching the descriptions of unbalanced and balanced forces. Balanced forces do not change an object's motion, while unbalanced forces cause changes in motion, including direction and speed.

Which statement explains the rocket’s motion?

• The inertia of the water and air must be overcome.

• The force of gravity of the rocket is greater than the water.

• The force of gravity must be overcome to achieve lift.

• For every action there is an equal and opposite reaction.

Answer explanation

The correct statement, 'For every action there is an equal and opposite reaction,' explains the rocket's motion as it propels itself upward by expelling gas downward, demonstrating Newton's third law of motion.

Tags

NGSS.MS-PS2-1

NGSS.MS-PS3-5

The graph shows the distance an object travels over time. Which table correctly describes the object's motion during each interval of time?

• 
• 
• 
• 

Tags

NGSS.MS-PS3-1

Which of the following quantities is a velocity?

• 25 m/s

• 3 g/L in weight

• 15 m/s²

• 10 km/hr eastward

Answer explanation

Velocity is defined as speed with a direction. '25 m/s' is a speed, while '10 km/hr eastward' includes direction, making it a velocity. '15 m/s²' is acceleration, and '3 g/L' is a concentration, not a velocity.

The picture shows a tractor trailer. Why do tractor trailers take more time to speed up and slow down than regular cars?

• A. Tractor trailers have less mass and require less force to move.

• B. Tractor trailers have more mass and require more force to move.

• C. Tractor trailers have less mass and require more force to move.

• D. Tractor trailers have more mass and require less force to move.

Answer explanation

Tractor trailers have more mass than regular cars, which means they require more force to accelerate and decelerate. This increased mass results in longer times to speed up and slow down, making option B the correct choice.

Tags

NGSS.MS-PS2-1

NGSS.MS-PS2-2

How could the speed of a car be determined?

• distance and time

• distance and size

• weight and time

• weight and size

Answer explanation

The speed of a car can be calculated using the formula speed = distance / time. Therefore, knowing both the distance traveled and the time taken allows us to determine the car's speed, making 'distance and time' the correct choice.

Tags

NGSS.MS-PS3-1

Suppose 15 children who weigh the same are playing a game of tug-of-war. Five children pull with 5 newtons of force, while ten children pull with 10 newtons of force in the opposite direction. How can one determine the net force on the rope?

• The forces are in the same direction, so the newtons can be added.

• The forces are in opposite directions, so the newtons can be divided.

• The forces are in opposite directions, so the newtons can be subtracted.

• The newtons are in the same direction, so the newtons can be multiplied.

Answer explanation

The forces exerted by the children are in opposite directions: 5 newtons pulling one way and 10 newtons pulling the other. To find the net force, we subtract the smaller force from the larger force, resulting in a net force of 5 newtons.

Tags

NGSS.MS-PS2-2

Celia is riding her bicycle and suddenly realized her brakes are not working. Onto which surface would be the best to steer her bike if she wants to slow down?

• grass

• concrete

• asphalt

• tile

Answer explanation

Steering onto grass is the best option for Celia to slow down because it provides more friction and resistance compared to concrete, asphalt, or tile, which are smoother and would allow her to continue moving faster.