Motion and Momentum S8P3: Students will investigate relationship between force, mass, and the motion of objects.

Matter and Motion All matter in the universe is in motion. We are in motion because we are on Earth, and Earth is revolving around the sun. The blood in our body is being circulated. Our heart is always beating.

Changing Position Before we can know our position we must first know that everything is in motion. The distance we have to travel to get to a football game is how far away it is from our spot. It may be 2 blocks away or 50, this is the distance. The displacement includes the distance between the starting and ending points.

Speed Speed is the distance an object travels in a unit of time. Speed can be calculated by dividing distance by time.

The average speed is found by dividing the total distance traveled by the total time taken. Instantaneous is an objects speed at one particular

Graphing Motion A distance-time graph can be used to compare the speeds of objects. Ex. After one second student A travels 1.5m. Student B traveled 1m for the first second.

Velocity The velocity of an object is the speed of the object and the direction of its motion. The velocity can change if the object’s speed changes, its direction of motion changes, or they both change. Suppose a car is traveling at a speed of 40 km/h north then turns left at an intersection and continues on with a speed of 40 km/h. The speed of the car is constant at 40 km/h, but the velocity changes from 40 km/h north to 40 km/h west.

Acceleration Acceleration is the change in velocity divided by the time it takes for the change to occur. When we accelerate we either speed up, slow down, or change direction.

Calculating Acceleration In this equation, time is the length of time over which the motion changes. When we speed up the acceleration is positive and when we slow down the acceleration is negative.

Mass & Inertia Mass is the amount of matter in an object. It also measures the quantity of matter. Inertia is the tendency of an object to resist a change in its motion.

Momentum The momentum of an object is a measure of how hard it is to stop the object, and it depends on the object’s mass and velocity. The law of conservation of momentum states that the total momentum of a group of objects remain constant unless outside forces act on the group. For example when a group of bowling pins are hit by a bowling ball the law of conservation of momentum falls in place. Because the bowling pins momentum are interrupted by the bowling ball.

In some collisions like in bumper cars the cars hit each other, but as soon as they hit they bounce off, or in football when one player tackles the other.

Explain the relationship between each pair. Review Questions Explain the relationship between each pair. Speed - Velocity Velocity - Acceleration Velocity - Momentum Momentum - Law of Conservation of Momentum Mass - Momentum Mass - Inertia

7. Momentum - Inertia 8. Average Speed - Instantaneous Speed 9. What measures the quantity of matter? 10. How do we calculate speed?

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