Vocabulary # 3 ( How Levers Work)

Definitions

1. simple machine: a device with few parts that makes it easier to do work
2. effort force: the force applied to a machine
3. resistance force: the force that a machine acts against
4. lever: a simple machine made of a rigid bar on a pivot point
5. fulcrum: the pivot poin of a lever
6. mechanical advantage: the number of times a machine multiplies the force applied
7. pulley:  a grooved wheel that turns by the action of a rope in the groove
8. wheel and axle: a simple machine made of a handle or axis attached to the center of a wheel

Sentences and illustration

1. When simple machines are combined, the result is a complex machine.

2. Effort force is what you apply to a machine.

3. Resistance force is the force the machine acts against.

4. All levers have rigid bars that rest on a pivot.

5. The pivot point in the lever is called fulcrum.

6. A machine's mechanical advantage is found by dividing the distance effort arm moves by the distance the resistance arm moves as the machine does work.

7. A pulley system is made up of several pulleys.

8. Wheel and axle are consists of a wheel that applies the effort force and smaller axle that outputs the force.

Vocabulary # 2 ( Energy and Work)

Definitions

1. potential energy: the energy stored in an object or material
2. gravitational potential energy: the potential energy of an object located above the ground
3. kinetic energy: the energy of a moving object
4. work: force applied to an object times the distance the object moves

Sentences and illustration

1. Potential energy exists when there is a force that tends to pull an object back toward some lower energy position.

2. The greater the object's height and weight, the more gravitational potential energy it gains.

3. A moving object has energy due to its motion.

4. Scientists say that work is applying force to an object to move it trough a certain distance.

Vocabulary # 1 ( Newton's law of motion)

Definitions

1. force :a push or pull exerted by one object on another
2. friction: a force that opposes the motion of an object in contact with a surface
3. drag force: a force that opposes the motion of an object through a liquid or gas
4. gravity: a force of attraction that exist between all objects with mass
5. net force: the combined effect of all the forces acting together on an object
6. balanced forces: forces that cancel each other out when acting on a single object
7. unbalanced forces: forces that do not cancel each other when acting on a single object
8. inertia: the tendency of an object to oppose a change in motion
9. momentum: the mass of an object multiplied by its velocity

Sentences and illustrations

1. Pushing a door is a simple example of force.

2. Fiction opposes motion in contact with surfaces.

3. Drag force is similar to the force of sliding friction because both oppose motion.

4. Mass is what produces gravity and it is measured in kilograms.

5. Scientists believe that net force is equel to zero.

6. You can tell when forces are balanced because the motion of th object does not change.

7. When forces are unbalanced , it means the net force is not zero.

8. Passengers in car experience inertia as the car turns.

9. Momentum is simply mass times velocity.