MC

8th Grade Integrated Science

Standard:  04

Objective:  02.  Examine the force exerted on objects by gravity.

ILO:

 

 

What are the metric units of measurement for weight?

            a.  cm3

            b.  mL

            c.  g

            d.  N

 

Correct Answer:  d

 

MC

8th Grade Integrated Science

Standard:  04

Objective:  02.  Examine the force exerted on objects by gravity.

ILO:

 

 

How are mass and weight different?

            a.  mass depends on how much matter is in the object but weight doesnÍt

            b.  weight depends on how much matter is in the object but mass doesnÍt

            c.  weight depends on gravity but mass doesnÍt

            d.  mass depends on gravity but weight doesnÍt

 

Correct Answer:  c

 

MC

8th Grade Integrated Science

Standard: 04

Objective: 02.  Examine the force exerted on objects by gravity.

ILO:

 

 

In which of the situations would a given weight remain the same?

a.     on Earth and on the moon

b.     on Earth and in a space station orbiting above the Earth

c.     in Utah and in Wyoming at the same altitude

d.     on Earth and Mars

 

Correct Answer: c

 

MC

8th Grade Integrated Science

Standard:  04

Objective:  02.  Examine the force exerted on objects by gravity.

ILO:

 

 

How are mass and weight different?

            a.  they both depend on the local gravity system

            b.  mass depends on the weight and weight depends on the mass

            c.  weight depends on the local gravity system but mass does not

            d.  mass depends on the local gravity system but weight does not

 

Correct Answer:  c

 

MC

8th Grade Integrated Science

Standard:  04

Objective:  02.  Examine the force exerted on objects by gravity.

ILO:

 

 

What force naturally pulls objects toward the center of the earth?

a. Buoyant force

b. Elastic force

c. Electrical force

d. Gravitational force

 

Correct Answer: d

 

MC

8th Grade Integrated Science

Standard:  04

Objective:  02.  Examine the force exerted on objects by gravity.

ILO:

 

 

Which of these best describes the relationship between the mass of an object and EarthÍs gravitational pull on the object?

            a.  the smaller the mass of the object, the greater is EarthÍs gravitational pull on it

            b.  the smaller EarthÍs gravitational pull, the greater the mass of the object

            c.  the greater the mass of the object, the greater is EarthÍs gravitational pull on it

            d.  the greater EarthÍs gravitational pull, the greater the mass of the object

 

Correct Answer:  c

 

MC

8th Grade Integrated Science

Standard:  04

Objective:  02.  Examine the force exerted on objects by gravity.

ILO:

 

 

How could you decrease the gravitational pull between two objects?

            a.  increase their respective masses

            b.  make the surface of one of them rough

            c.  decrease the distance between them

            d.  increase the distance between them

 

Correct Answer:  d

 

MC

8th Grade Integrated Science

Standard:  04

Objective:  02.  Examine the force exerted on objects by gravity.

ILO:

 

 

Which of these affects the gravitational pull between two objects?

            a.  how many layers each one has

            b.  how fast one of them is moving

            c.  how far apart they are

            d.  whether they have a smooth or rough surface

 

Correct Answer:  c

 

 

I

8th Grade Integrated Science

Standard:  04

Objective:  02.  Examine the force exerted on objects by gravity.

ILO:

 

 

Mass

John

Mario

Brock

2 kg

35

40

37

4 kg

31

35

33

6 kg

22

26

29

 

Three boys, John, Mario, and Brock decided to see how many arm curls they could do without stopping.  An arm curl is performed by holding a barbell with the arm straight down and the hand facing forward, then bending the arm at the elbow and raising the barbell toward the shoulder.  The boys used 3 different barbells of increasing mass.  These curls were all done between 9 and 9:30 a.m. on the same day.

 

1.  What would be a good conclusion for this activity?

            a.  Mario is the strongest boy

            b.  Brock is the strongest boy

            c.  as the mass was increased, the number of curls decreased

            d.  as the number of curls decreased, the mass increased

 

2.  The independent variable is the variable you change, or allow to change.  What was the independent variable in this experiment?

            a.  barbells of different mass

            b.  time of day

            c.  number of lifts

            d.  which boy was lifting

 

3.  The dependent or responding variable is the one that changes as a result of the independent variable.   What was the dependent variable in this experiment?

            a.  barbells of different mass

            b.  time of day

            c.  number of lifts

            d.  which boy was lifting

 

4.  Which of these variables was a controlled variable?

            a.  barbells of different mass

            b.  time of day

            c.  number of lifts

            d.  which boy was lifting

 

Correct Answers:

            1.  c

            2.  a

            3.  c

            4.  b

 

I

8th Grade Integrated Science

Standard:  04

Objective:  02.  Examine the force exerted on objects by gravity.

ILO:

 

 

Martine needed to lift up a trunk onto a platform.  He attached a pulley above the trunk and used a rope through the pulley to lift the trunk up so Laura could slide the platform under and they could get the trunk on the platform.  Answer the following questions about this situation.

 

1.  Why was it easier for Martine to lift the trunk with the pulley rather than just lifting it?

a.     He increased the mechanical advantage by using a pulley.

b.     He decreased the mechanical advantage by using a pulley.

c.     He was able to let gravity help him by using the pulley.

d.     He was able to reduce gravity and that made lifting the trunk easier.

 

2.  How could Martine have made the task of lifting the trunk easier?

a.     use more pulleys

b.     have Laura do it

c.     use a lever attached to the pulley

d.     attach the pulley to an inclined plane

 

3.  What is the mechanical advantage of using a single pulley to lift the trunk?

a.     0

b.     about 1

c.     about 2

d.     the same as the weight of the trunk

 

Correct Answers:

1.     c

2.     a

3.     b

 

 

I

8th Grade Integrated Science

Standard:  04

Objective:  02.  Examine the force exerted on objects by gravity.

ILO:

 

 

 

A heavy ball is suspended on a rope.  A second ball is perched on a platform on top of a grooved ramp where dominoes are lined up below, with a third ball after them and a cup positioned below.

 

NOTE:  The teacher might not want to use all of these items.

 

1.  Study the drawing above.  Infer what will happen if the heavy ball is released from where it is currently.

            a.  the second ball will move slowly down the ramp but probably no dominoes will fall

b.  the second ball will move down the ramp and dominoes will fall but the third ball probably wonÍt move

c.  the second ball will move down the ramp, dominoes will fall, and the third ball might fall into the cup

            d.  the heavy ball will simply swing back and forth not moving the second ball

 

2.  Study the drawing above.  From which point would the heavy ball need to be released to get the third ball to fall into the cup?

            a.  A

            b.  B

            c.  C

            d.  D

 

 

 

 

 

3.  Why will the third ball not fall in the cup if the heavy ball is released from point D?

            a.  the heavy ball wonÍt hit hard enough to make the second ball go down the ramp

            b.  the heavy ball wonÍt reach the second ball

            c.  the heavy ball will hit the second ballÍs platform too hard

            d.  not enough energy from the heavy ball will be transferred to the second ball

 

Correct Answers:

            1.  d

            2.  a

            3.  b

 

E

8th Grade Integrated Science

Standard:  04

Objective:  02.  Examine the force exerted on objects by gravity.

ILO:

 

 

Explain projectile motion.  Use the space provided to draw an example of projectile motion.  If you were to take two identical objects and drop one off a building while at the same time throwing the other out horizontally off the same building, which would hit the ground first?

 

 

Ideal Answer:

            Projectile motion is motion in which there is a change in both the horizontal and vertical directions simultaneously.  An example would be the curved arc a ball would take if thrown horizontally off a building.  Both the object dropped straight down and the one set into projectile motion would reach the ground at the same time.  The only force acting on either ball once it is released from the hand is gravity.  The projectile motion results from the inertia of the object, which keeps it moving at a uniform rate in the horizontal direction and gravity, which accelerates it down, in the vertical direction.  Inertia is not a force, but a tendency of an object to keep doing whatever it is doing.

 

Scoring Guide:

            Explain projectile motion                                                         30%

            Draw an example of projectile motion                         20%

            Identify which object would hit the ground first                      10%

            Explanation of which object would hit the ground first           20%

            Correct spelling, punctuation and language use                       20%

 

 

P

8th Grade Integrated Science

Standard:  04

Objective:  02.  Examine the force exerted on objects by gravity.

ILO:

 

 

1.  Divide students into groups of 2-3.  Each group receives 100 popsicle sticks and a glue-stick.  Each groups is given the task* to build a structure that will hold a 500 g mass.  The groups with structures at least 30 cm tall that support the weight will receive 25 points.  This should take only one class period.  Tape, string, and staples are not allowed.  Not all the wooden sticks need to be used.  The one group with the tallest structure that supports the weight receives 5 bonus points.  This project is worth 25 points.  Display the scoring guide on the board or overhead.

 

*Alternate task:  build a bridge at least 20 cm long and 10 cm above desk at highest point in the middle of the bridge.  A specified toy car or truck must be able to cross the bridge without disaster.

 

Scoring Guide:

Tallest structure over 30 cm that supports the weight              30

Structure at least 30 cm tall and supports the weight                           25

Structure at least 30 cm tall but doesnÍt support weight                      15

20 cm > structure < 30 cm tall and supports the weight                       20

10 cm > structure < 20 cm tall and supports the weight                       15

Structure < 10 cm tall and supports the weight                                    10

All others                                                                                             0