Physical Science Practice

During the first 30 minutes, 12 atoms have decayed. What is the half-life of this radioactive element?

• 12 minutes

• 15 minutes

• 24 minutes

• 30 minutes

Tags

NGSS.HS-PS1-8

A research lab has a sample of the radioactive isotope silver-118, which decays to cadmium-118 and has a half-life of approximately 4 seconds. Approximately, what percentage of the original silver-118 sample will remain undecayed after 12 seconds?

• 12.5 %

• 25.0 %

• 33.3 %

• 50.0 %

Tags

NGSS.HS-PS1-8

Suppose you extract one gram of carbon from an ancient wooden hammer handle. You find that your ancient gram of carbon is half as radioactive as a gram of carbon extracted from a tree branch that was cut today. The half-life of C-14 is 5,730 years. Assuming that today's ratio of C-14 to C-12 is the same as when the hammer was made, how old would you estimate is the hammer?

• 1,432.5 years old

• 2,865 years old

• 5,730 years old

• 11,460 years old

Carbon-14 is used in determining the age of fossils. It has a half-life of 5,730 years. A sample has 100g of carbon-14 present initially. Carbon-14 is effective for radioactive dating as long as there is 0.10g of this sample remaining. At which THREE times will carbon-14 dating still work for this sample?

• 34,800 years as 1.56g of carbon-14 remain

• 17,190 years as 12.5g of carbon-14 remain

• 2,865 years as 50g of carbon-14 remain

• 1,200 years as 1.40g of carbon-14 remain

• 51,570 years as 0.195g of carbon-14 remain

A student is studying the movement of an object undergoing uniform motion. What is the velocity of the object?

• Its velocity is zero.

• Its velocity is constant.

• Its velocity is increasing.

• Its velocity is decreasing.

The graph depicts the displacement versus time for a car traveling on a round trip. How could the student estimate the average speed in the first 8 hours?

• take the total distance traveled divided by 8 hours

• find the slope of the line segment ABC divided by 8 hours

• add the distance covered in line segment AB to BC multiplied by 8 hours

• add the distance covered in line segment AB and BC divided by 8 hours

Tags

NGSS.MS-PS3-1

Tanisha uses a remote-controlled car with a sensor to investigate its motion. She creates a velocity vs. time graph of the data. Which TWO statements must be TRUE?

• The car has a constant velocity for the first 3 seconds, then stops moving from 3 to 7 seconds.

• The car accelerates for the first 3 seconds, then has zero acceleration from 3 to 7 seconds.

• The car has a constant velocity for the first 3 seconds, then decelerates from 3 to 7 seconds.

• The car has an increasing velocity for the first 3 seconds, then stops moving from 3 to 7 seconds.

• The car has an increasing velocity for the first 3 seconds, then has a constant velocity from 3 to 7 seconds.

Tags

NGSS.MS-PS2-2

NGSS.MS-PS3-1

Which of the following choices correctly describes the conclusion of the students?

• The average speed of the toy car increases as the distance increases.

• The average speed of the toy car decreases as the distance increases.

• The average speed of the toy car remains the same regardless of the distance.

• The time it takes for the toy car to travel a certain distance is not consistent.

Newton's Third Law of Motion states that for every action there is an equal and opposite reaction, as shown in the illustration. Which is another characteristic of these forces?

• Action and reaction forces always come in pairs.

• Action and reaction forces act on the same object.

• Action and reaction forces do not act simultaneously.

• Action and reaction forces are greater for the object with the greater mass.

Tags

NGSS.MS-PS2-1

In the picture, someone kicked a soccer ball that was sitting on the ground. Which BEST explains the motion of the foot and soccer ball in the picture?

• The foot was in motion and collided with the soccer ball. After the collision, the ball started moving at a constant velocity.

• The foot was in motion and collided with the soccer ball. The soccer ball transferred an unbalanced force to the foot and caused it to stop moving.

• The soccer ball was at rest. The foot was in motion and collided with the ball. The foot continued moving at the same velocity and in the same direction.

• The soccer ball was at rest. The foot was in motion and collided with the ball. The foot transferred an unbalanced force to the ball and caused it to start moving.

Tags

NGSS.MS-PS2-1