Physical Science 8th Grade Exam! Lets Pass Together.

Stephanie leaves the house and rides to the local farmer's market with her grandmother. The graph below illustrates their trip. 

Which line segment represents the time the car is returning to the house? 

• Segment A

• Segment B

• Segment C

• Segment D

Answer explanation

Segment D represents the time the car is returning to the house as it shows a decrease in distance traveled, indicating the car is heading back home.

To make an object move you must first apply ---

• an opposing force

• an unbalanced force

• a stationary force

• a vertical force

Answer explanation

To make an object move you must first apply an unbalanced force, as it is necessary to overcome inertia and initiate motion.

Tags

NGSS.MS-PS2-2

Oliver stepped onto a three-car subway train with standing room only. What caused him to fall backward into other riders when the train suddenly moved forward?

• He was riding in the last car of the train.

• He had heat exhaustion from the overcrowded train.

• Oliver's body resisted a change in the subway train's inertia.

• Oliver's body was responding to the force of gravity.

Answer explanation

Oliver's body resisted a change in the subway train's inertia.

Tags

NGSS.MS-PS2-2

Which law of motion predicts that a moving hockey puck will continue to move in the same direction at the same speed unless acted upon by another force?

• Newton's First Law of Motion

• Newton's Second Law of Motion

• Newton's Third Law of Motion

• Newton's Law of Universal Gravitation

Answer explanation

Newton's First Law of Motion states that an object in motion will stay in motion unless acted upon by an external force, explaining why a moving hockey puck will continue in the same direction at the same speed.

Which law explains the relationship among mass, force and acceleration?

• Universal Law of Gavitation

• Newton's First Law of Motion

• Newton's Second Law of Motion

• Newton's Third Law of Motion

Answer explanation

Newton's Second Law of Motion explains the relationship among mass, force, and acceleration by stating that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass.

Tags

NGSS.MS-PS2-2

The force of an object, with a certain mass accelerating at a certain rate, can be determined by using the equation below.

force = mass x acceleration

Which object would have the greatest force?

• A 5 kg object accelerating at 10 m/s

• A 5 kg object accelerating at 20 m/s

• a 20 kg object accelerating at 4 m/s

• a 20 kg object accelerating at 3 m/s

Answer explanation

Choose the 5 kg object accelerating at 20 m/s as it would have the greatest force based on the equation force = mass x acceleration.

Tags

NGSS.MS-PS2-2

According to Newton's Third Law of Motion, if Mike pushes down on the springboard to being his dive, what is the reaction force?

• Mike splashing into the water

• The springboard pushing Mike into the air

• The height of the water when Mike enters the water

• The sound the board makes as he pushes into the air

Answer explanation

According to Newton's Third Law of Motion, the reaction force when Mike pushes down on the springboard is the springboard pushing Mike into the air.

Tags

NGSS.MS-PS2-1

If the man and the ball travels 90 m in 9 seconds, what is their average speed?

• 10 m/s

• 180 m/s

• 99 m/s

• 10 meters

Answer explanation

To find average speed, divide total distance by total time. Here, 90 m / 9 s = 10 m/s. Therefore, the average speed is 10 m/s.

Tags

NGSS.MS-PS3-1

Person on the left = 45 N

Person on the right = 32 N

What is the net force?

• zero N

• 10 N

• 77 N

• 13 N

Answer explanation

To find the net force, we need to add the forces together. 45 N - 32 N = 13 N. Therefore, the net force is 13 N.

Tags

NGSS.MS-PS2-2

NGSS.MS-PS2-1

What is speed?

• Speed is how far something travels in one hour.

• Speed is how fast it takes something to travel a set distance

• Speed is the distance something travels in a set amount of time.

• Speed is the change in velocity of something.

Answer explanation

Speed is the distance something travels in a set amount of time.

Tags

NGSS.MS-PS3-1