Volusia District Science Office week 6. SC.6.P.13.1 –Types of Forces Sabrina and Gabriela are ice skating at a local rink. Sabrina braces herself against.

Volusia District Science Office week

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SC.6.P.13.1 –Types of Forces Sabrina and Gabriela are ice skating at a local rink. Sabrina braces herself against a wall and pushes Gabriela across the ice. After the push, Gabriela slides by herself across the ice. Which of the following best describes the forces acting on Gabriela as she moves across the ice after Sabrina is no longer touching her?

A. The force of friction between the ice and her skates acts on Gabriela the entire time she slides across the ice.

B. There are no forces affecting Gabriela’s motion once Sabrina is no longer pusher her.

C. The force from the push continues to act on Gabriela for a while, but its strength gradually fades.

D. The force from the push continues to act on Gabriela the entire time she slides across the ice.

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SC.6.P.13.1 –Types of Forces Playing hockey on inline skates instead of on ice skates is a growing sport in Florida. Players use a hockey stick to hit a puck across the floor of a rink. After the puck leaves the stick, which force or forces are exerted on the puck?

A. Friction and dragB. Drag onlyC. Friction and the applied force from the

hockey stickD. Friction, drag and the applied force from the

hockey stick

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SC.6.P.13.1 –Types of Forces

Mr. Thompson explained that some forces can act on an object without actually coming into contact with the object. He listed examples of noncontact forces on the board. Which force should NOT be included in Mr. Thompson’s list.

A. electricalB. frictionalC. gravitationalD. magnetic

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SC.6.P.13.1Types of Forces1. C2. D3. B

Overall Summary:

Contact forces require two or more objects to physically touch in order to cause a change. Friction is a contact force. Forces acting at a distance do not have to touch. Gravity, electricity, and magnetism are all forces that act a distance.

Discussion?

SC.6.P.13.2 – Distance between Bodies

A meteor moving through space speeds up as it gets closer to Earth’s atmosphere. What force causes the meteor’s speed to decrease as it moves through Earth’s atmosphere?

A. GravityB. Magnetic attractionC. FrictionD. Electrical attraction

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SC.6.P.13.2 – Distance between BodiesTwo new planets are discovered called planet X and planet Y. The planets have identical volumes, but the mass of planet X is two times greater than the mass of planet Y. If two identical space ships land on both planets, which of the following will be true?

A. The mass of the space ship on planet X will be greater than the mass of the space ship on planet Y.

B. The weight of the space ship on planet Y will be greater than the weight of the space ship on planet X.

C. The mass of the space ship on planet Y will be greater than the mass of the space ship on planet X.

D. The weight of the space ship on planet X will be greater than the weight of the space ship on planet Y.

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SC.6.P.13.2 – Distance between Bodies

Chelsea is reading about astronauts. She discovers that astronauts weigh less on the Moon than they do on Earth. Which of the following best explains why astronauts weigh less on the Moon than on Earth?

A. Earth’s gravity is stronger than the Moon’s.B. Astronauts have less density on the Moon.C. Astronauts have more mass on Earth than on

the Moon.D. Earth has more friction than the Moon.

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SC.6.P.13.2Gravity, Distance, and Mass4. C5. D6. AOverall Summary: Gravity is a force of attraction between two or more

objects. It acts at a distance but as the distance between the two objects increases the magnitude of the force decreases. The force of gravity between two objects will also increase with increasing mass.

Discussion?

SC.6.P.13.3 – Applied ForcesA sailboat moving southward through the water experiences a force of 2500 N exerted by the wind on its sails. The water and air resistance apply a force of 1500 N in the opposite direction of the sailboat’s direction of travel. Which of the following best describes the forces exerted on the sailboat?

A. The forces are unbalanced in the direction of motion.B. The forces are unbalanced in the direction opposite

the motion.C. The forces on the boat are balanced and the boat is

speeding up and moving northward.D. The forces on the boat are balanced and the boat is

speeding up and moving southward.

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SC.6.P.13.3 – Applied ForcesA skydiver jumps from an airplane and opens his parachute. At some point during his fall the downward force of gravity on the skydiver is equal to the upward force of drag on the parachute. Which of the following best describes the skydiver’s motion at this point?

A. The skydiver is moving from side to side.B. The skydiver is moving at a constant speed.C. The skydiver is decelerating upward.D. The skydiver is accelerating downward.

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SC.6.P.13.3 – Constant Speed

Gabe rides his bike to school everyday. He always takes the same path and the same amount of time. He calculated that his average speed from his house to his school was constant. Which of the following is true if he travels at a constant speed?

A. The forces acting on the bike are balanced.B. The bike has a constant positive acceleration.C. The bike has a constant negative accelerationD. The forces acting on the bike are not balanced.

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SC.6.P.13.3Balanced and Unbalanced Forces7. A8. B9. A

Overall Summary:

Forces are a push or a pull on an object. They can change the speed, direction, or both of something they interact with. If two ore more forces are applied in opposite directions and their magnitudes are equal then they are balanced. Unbalanced forces result in movement or a change in direction.

Discussion?

SC.6.E.6.1 – Erosion

Earth’s oceans are estimated to contain over 50 million billion tons of dissolved salts. The Atlantic Ocean has an average salt concentration of 2.2 pounds of salt per cubic foot of water. Which of the following is the primary source of dissolved salts in the ocean?

A. Precipitation from stormsB. Human activitiesC. Minerals carried from the land by riversD. Weathered stones at mid-ocean ridges

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SC.6.E.6.1 – Erosion & Weathering

Many people often confuse the terms “weathering” and “erosion.” which of the following events is the best example of erosion?

A. The rolling of a pebble along the bottom of a streambed

B. The splitting of sedimentary rock because water has frozen in a crack

C. The dissolving of rock by rainwaterD. The crumbling of bedrock to form soil

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SC.6.E.6.1 –Slowing ErosionFarmers all over the world take steps to slow down the erosion of soil. Which of the following would NOT be an example of a method of slowing soil erosion?

A. Covering bare soils with decaying plants such as dead grass or hay

B. Alternating rows of ground cover crops and crops that leave much of the ground exposed

C. Planting trees as a barrier to break the force of high winds

D. Adding fertilizer to enrich the soil for higher productivity

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SC.6.E.6.1Erosion, Weathering, Deposition

10. C11. A12. D

Overall Summary: Weathering is the wearing down of rock into smaller particles.Erosion is the movement of particles from some location.Deposition is the build-up of particles that were moved from a

location.All three forces above work together to continuously change the

surface of the Earth. Weathering can be physical (grinding) or chemical (acid rain.)

Discussion?