Force & Motion

Essential Questions What are the major forces that affect motion? How do forces affect motion? What are the characteristics of motion? What are the tools used to measure motion? How can I calculate speed? What is inertia?

What are the major forces that affect motion?

A FORCE is a push or pull that causes changes in motion. Forces A FORCE is a push or pull that causes changes in motion.

Types of Forces Friction Gravity Magnetic Remember These??

Friction When a soccer ball is kicked across the grass, it eventually slows down. Why? FRICTION Friction is a force that works against motion Friction can make things slow down or stop, or it can keep things from moving at all.

Gravity is the force that pulls things down to the earth

Magnetic Force They stick together! Take a magnet and hold it near some paper clips. What happens?? They stick together!

Magnetic Force Anything that attracts iron is considered magnetic. That’s why all the paper clips were attracted to the magnet. Paper clips contain iron. The force of a magnet is called the magnetic force.

A magnet is a piece of metal that pulls or attracts things which have iron or steel in them. The most common magnets are in the shape of a bar or horseshoe. N S Magnetic Poles

How do forces affect motion?

Forces can affect motion in several ways: → They can make objects start moving. → They can make objects move faster. → They can make objects move slower. → They can make objects stop moving. → They can make objects change direction.

What are the characteristics of motion?

Characteristics of Motion The motion of an object can be described by its: Position Direction Speed Velocity Position, direction, speed, & velocity can be changed by forces that act on the object.

Position & Direction Position is the location of an object Motion can also be described using directions such as north, south, east, & west. Direction of an object depends on the direction of the force.

Speed Position and direction are helpful in describing motion. Yet motion also occurs over time. For example- You threw a football 20 meters. But did the football go 20 meters in 2 minutes? 2 seconds? Speed is the measurement of distance over time. You can use a stopwatch to measure speed

Velocity Velocity is the object’s speed BUT includes direction Remember, DIRECTION includes north, south, east and west- following the points of a compass. For example- the football that was thrown 60 meters in 2 seconds is traveling 30 meters per second (60/2 = 30). You MUST include direction for velocity. So your answer might really be 30 meters per second north! States the direction the ball traveled

Acceleration Acceleration occurs when an object speeds up, slows down (deceleration), or changes direction. Acceleration is a change in velocity.

Let’s Review- Matching Motion Velocity Direction Speed Acceleration A change in Velocity Which way an object is going A change in position Speed in a particular direction Distance traveled in a certain amount of time

What are the tools used to measure motion?

Measuring Motion Scientists use many tools to measure motion: Commonly used to measure direction is the compass. A meterstick is commonly used to measure distance between one position and another. A stopwatch is used to measure time

Calculataing speed

Speed TRY THIS OUT: Speed = Distance ÷ Time D_ Speed = T A car travels 80 miles in 40 minutes. What is the speed of the car?

Answer: Speed = distance ÷ time Speed = 80 miles ÷ 40 minutes

Speed Speed = Distance ÷ Time TRY THIS OUT A plane travels 1000 miles in 5 hours. What is the speed of the plane?

Answer: Speed = distance ÷ time Speed = 1000 miles ÷ 5 hours Speed = 200 miles/hr

What is Inertia?

Inertia Can an object move on its own? NO!!!!!!!!!!!!!! INERTIA is the tendency of an object to remain at rest if it is resting or stay in motion if it is moving. If a soccer ball is at rest, it will remain at rest until a force (such as a kick) acts upon it.

Inertia The more mass an object has, the more inertia it has. A big truck has more inertia than a car. This is because it is harder to get a truck moving and harder to stop it.

Let's Review

Let’s Review A kicked soccer ball slows down and eventually stops moving because of A.) inertia and friction B.) inertia and gravity C.) friction and gravity D.) gravity and magnetism A.

Let’s Review Mary and Andrew were playing with their small toy cars. They set up a ramp to see which car would travel the farthest. Which of the following tools would be best to use to measure how fast and far the cars traveled? A.) stopwatch and balance scale B.) measuring tape and stopwatch C.) measuring tape and balance scale D.) balance scale and thermometer B.

Let’s Review What would Mary and Andrew need to know in order to calculate the average speed of the cars? A.) distance and direction B.) time and acceleration C.) acceleration and distance D.) distance and time D.

Let’s Review B. Which of the following would take more force to lift? A.) 1 pound of feathers B.) 1 pound of rocks C.) 1 pound of cotton candy D.) 1 pound of coffee B.

Let’s Review A ping pong ball, baseball, kickball, and tennis ball were in a box on the playground. Which of the balls would take more force to throw? A.) kickball B.) tennis ball C.) baseball D.) ping pong ball A.

Let’s Review Jimmy and his friend were kicking soccer balls down the field. What would Jimmy need to do to kick the ball farther than his friend? A.) Run faster down the field B.) Stop the ball C.) keep kicking the ball with a stronger force in the same direction D.) keep kicking the ball with the same force in the same direction C.