MATTER IN MOTION

SPEED

• Speed - the rate at which an object moves
• Formula: S = D/T
• Speed = distance divided by time

EXAMPLE OF SPEED

• Danny swam 200 meters in 2 minutes. What was his speed per minute?
• Formula: S = D/T
• S = 200/2 = 100 meters per minute
• Tommy's speed was 100 meters per minute.

FUN FACTS ABOUT SPEED

• Sound travels 5 times faster underwater then in air
• Sound travels 15 times faster through steel than air
• A woodpecker can peck 20 times in a second

AVERAGE SPEED

• Average Speed - the total distance traveled divided by the total time taken to travel it
• Formula: AS = TD/TT
• Average speed = total distance divided by total time

AVERAGE SPEED EXAMPLE

• Jesse rode his Harley for 5 hours. He traveled 300 miles in total. What was his average speed?
• Formula: AS = TD/TT
• AS = 300/5 = 60 miles per hour
• Jesse's average speed was 60 miles per hour.

FUN FACTS ABOUT AVERAGE SPEED

• The average speed of a skydiver is 124 mph
• The average speed of traveling light is 186,000 mph
• The average speed of a steamboat is 20 mph

VELOCITY

• Velocity - the speed of an object in a certain direction
• Formula: V = D/T
• Velocity = distance divided by time

VELOCITY EXAMPLE

• A plane flew 300 miles North. Then, flew another 300 miles. This flight was completed in 4 hours. What was the velocity of the plane?
• Formula: V = D/T
• V = 600/4 = 75 miles per hour North
• The velocity of the plane was 75 miles per hour North.

FUN FACTS ABOUT VELOCITY

• When something changes speed it also changes velocity

ACCELERATION

• Acceleration - the rate at which velocity changes over time
• Formula: A = Vf - Vi/ Tf - Ti
• Acceleration = final velocity - initial velocity divided by final time - initial time

ACCLERATION EXAMPLE

• Calculate the accleration of a roller coaster that moves at a velocity of 15/s. After 3 seconds it's velocity increases to 30m/s.
• Formula: Vf - Vi/Tf - Ti
• 30 - 15/3 = 15/3 = 5 meters per second
• The accleration of the roller coaster is 5 meters per second

FUN FACTS ABOUT ACCLERATION

• One cause of accleration is gravity

NET FORCE

• Net force - the combination of forces acting on an object
• Formula: it just depends on the direction of the forces, but you add the force and direction together
• 50W + 30W = 80W

NET FORCE EXAMPLE

• Stephanie and D.J were pushing their car with forces of 40N and 50N. What was the net force?
• Formula: add the numbers and direction
• 40N + 50N = 90N
• The Net force applied was 90N.

NET FORCE FUN FACTS

• A large net force is needed to change something's speed or direction