1. Assessment Study Guide Answers
Mr. Schmidt
Portola Middle School
8th Grade Physical Science
1/16/2019

2. 1. The velocity of a car is determined by its speed and its direction.
1/16/2019

3. 2. In which of these units can density be expressed?
a. milliliters per gram
b. grams per liter
c. milliliters per meter
d. cubic centimeters per gram
1/16/2019

4. The velocity changed because the bus’ speed changed.
3. After a bus left a bus station, it began to move at a faster rate. What happened to the velocity of the bus?
The velocity changed because the bus’ speed changed.
1/16/2019

5. Time = 3 activities X 2 hours each Time = 6 hours
4. During her winter vacation, Karen hiked for 60 km, rode a boat for 100 km, and drove in a car for 320 km. Each activity took her 2 hours to complete. What is Karen’s average speed?
Distance = 60km + 100km km
Distance = 480 km
Time = 3 activities X 2 hours each
Time = 6 hours
Speed = Distance ÷Time
Speed = 480 km ÷ 6 hrs = 80 km/hr
1/16/2019

6. Upward and Equal to the weight of the water displaced by the ice cube
5. What is the direction and size of the buoyant force acting on an ice cube floating in water?
Upward and Equal to the weight of the water displaced by the ice cube
1/16/2019

7. Anesto raced at a higher average speed than Oscar
6. During a race, Oscar reached a higher top speed than Anesto, but Anesto won the race. What must have happened for Anesto to win?
Anesto raced at a higher average speed than Oscar
1/16/2019

8. D = m/V Density = Mass ÷ Volume 7. What is the formula for Density?
1/16/2019

9. The lighter marble had greater acceleration
8. Katherine threw marbles at a target. The marbles were the same volume, but one marble had a greater mass than the other. If thrown in the same way with equal force, which one had the greatest acceleration? Which one had the least acceleration?
The lighter marble had greater acceleration
The greater marble had least acceleration
1/16/2019

10. The direction to walk from the door.
9. Mr. Schmidt gave his students directions:
Walk at a 90 degree angle from the front door of Room 111 until you exit the B Building. 15 meters from the door you will find an envelope with the next directions
What additional information do Mr. Schmidt’s students need to find the envelope?
The direction to walk from the door.
1/16/2019

11. FRICTION and AIR RESISTANCE
10. Jasmine is riding a bicycle. When Jasmine applies force to the pedals, she begins to move forward. What combination of forces acts in the opposite direction of the bicycle’s forward motion?
FRICTION and AIR RESISTANCE
1/16/2019

12. The car changed direction
11. Traveling down a straight road, a car changed velocity while its speed remained constant. What caused this to happen?
The car changed direction
1/16/2019

13. There was more friction on the iron block than on the ice block
12. Andrew released a block of iron and a block of ice at the same time from the top of a slide. Which block would reach the bottom first, and why?
ICE BLOCK
There was more friction on the iron block than on the ice block
1/16/2019

14. Speed = Distance ÷ Time Distance = 10 meters Time = 5 hours
13. A lady bug crawls 10 meters up a tree in 5 hours. What is the lady bug’s average speed?
Speed = Distance ÷ Time
Distance = 10 meters
Time = 5 hours
Speed = 10 meters ÷ 5 hours
Speed = 2 m/hr
1/16/2019

15. 14. In which example can velocity be determined?
a. Brian walks 10 km per hour.
b. Erick drives for 200 km.
c. Adrian travels Northeast at 50 km per hour.
d. Joceline travels Southwest for 100 km.
1/16/2019

16. 15. An object will float in water if it has density less than 1
15. An object will float in water if it has density less than 1.0 grams per milliliter.
1/16/2019

17. The density of the object and the liquid.
16. What information do you need to know to predict whether an object will float in a liquid?
The density of the object and the liquid.
1/16/2019

18. 17. Label the forces acting on the apple to make it stationary.
1/16/2019

19. Distance Marble Traveled
18. The table below shows the results of an experiment that had identical ramps and identical marbles. Each student rolled a marble down the ramp and measured the distance. What might have affected the results?
Student
Distance Marble Traveled
Aidee
9.6 meters
Rolando
12.5 meters
Alphonso
9.4 meters
Joyce
9.3 meters
Rolando pushed the marble instead of letting it go
1/16/2019

20. Density = 5 g/ml Density = Mass ÷Volume Mass = 30 grams Volume = 6 ml
19. Scientists want to find the density of a 30 gram rock. After the rock was dropped into a 20 ml graduated cylinder the volume increased by 6 ml. What is the density of the rock?
Density = Mass ÷Volume
Mass = 30 grams
Volume = 6 ml
Density = 30 g ÷ 6 ml
Density = 5 g/ml
1/16/2019

21. 20. Jeanette placed a glass of orange juice on a ramp
20. Jeanette placed a glass of orange juice on a ramp. The glass of orange juice did not move. Why did the orange juice stay at the top of the ramp?
CORRECTION:
The Force of Friction EQUALS the force pulling the glass of orange juice down the ramp
1/16/2019

22. 12 meters in 30 seconds = 24 meters in 60 seconds
21. A lady bug traveled 12 meters in 30 seconds. How far would the lady bug travel in 60 seconds?
12 meters in 30 seconds = 24 meters in 60 seconds
1/16/2019

23. The table is exerting an upward force that opposes gravity.
22. Mr. Schmnidt’s coffee mug is resting stationary on his table. Why is the mug stationary?
The table is exerting an upward force that opposes gravity.
1/16/2019

24. 23. An ant crawled up a tree. The graph below shows how the ant’s height on the tree changed with time. Based on the slope of the line, how far will the insect have traveled in 60 seconds?
24 Meters
1/16/2019

25. Between 0-30 seconds. The slope was the same
24. During what interval did the car move at a constant speed? How do you know?
Between 0-30 seconds. The slope was the same
1/16/2019

26. At 35 Seconds. 25. At what time did the car reach the greatest speed?
1/16/2019

27. When the slope was the greatest.
26. Explain how to determine when the car reached the greatest speed?
When the slope was the greatest.
1/16/2019

28. Speed = 120 m ÷ 45 seconds = 2.67 m/sec
27. What was the average speed of the car as it moved along the 120 meter road?
Speed = 120 m ÷ 45 seconds = 2.67 m/sec
1/16/2019

29. 28. Jeff went running. The farther Jeff traveled from his starting point, the slower he jogged. Draw a distance vs. time graph that best shows Jeff’s speed while running.
1/16/2019

30. HOMEWORK: GO OVER THE TEST AT LEAST 10 TIMES KNOW THE QUESTIONS AND THE ANSWERS.
1/16/2019