2*1 Newton’s 1st Law: a running start (p132) WDYS? / WDYT? Figure skaters keep moving across the ice while seeming to expend to effort ___. A soccer ball continues to roll across the field after it has been kicked because ___.

2*1 Investigate (p132) When a ball is released to roll down a track and up the opposite side of the track, how does the vertical height that the ball reaches on the opposite side of the track relate to the vertical height from which the ball is released?”

2*1 Investigate (p132) ½ Sheet Hand-Out:

Physics Talk (p134-138) 1. Galileo’s Law of Inertia 2*1 Investigate showed release = recovered heights Galileo is the “father of modern science” From this same experiment and his many other observations, Galileo formed the Law of Inertia  natural tendency to stay at rest (or in constant, straight motion) Galileo also realized that objects do NOT stop on their own but because of force (a push or pull) like friction and air resistance

Which of the following carts has the greatest inertia? Physics Talk (p134-138) 2. Newton’s 1st Law of Motion Newton used Galileo’s Law of Inertia to develop his 1st Law of Motion  an object will remain at rest (or in constant, straight motion) UNLESS acted upon an unbalanced force Mass is a measure of an object’s inertia: the greater the mass, the greater the inertia Which of the following carts has the greatest inertia? a) 1kg at 5m/s b) 2kg at 3m/s c) 3kg at 1m/s d) 4kg at 1m/s

Physics Talk (p134-138) 3. SI System: The Kilogram 4. Running Starts Kilogram is the unit for mass where: 1kg = _____g 1kg = ___pounds 4. Running Starts In sports, the prior motion of a running start is very important EXAMPLE javelin =hand + elbow + shoulder + body Therefore, if you run prior to throwing a ball, it gets YOUR speed before you even release it!!! Acceleration  a change in speed at a specific time EXAMPLE starting, stopping, changing direction

Physics Talk (p134-138) 5. Frames of Reference Frame of Reference  a vantage point with respect to which position and motion may be described A cannon shoots a ball at 7m/s…If the cannon is on a resting skateboard, what is the cannon’s speed??? What if the skateboard was traveling at 3m/s??? Whenever you describe speed, you need to ask “Relative to what?”

Checking Up (p138) Inertia is __________. Newton’s 1st Law of Motion states __________. A __________ needs to act on an object to stop it from moving at a constant speed. An _____ _____ stops the motion of the ball. The __________ the mass, the greater the inertia. It is important to establish a frame of reference when describing the speed of the ball because _____.

PEQ (p142) A massive object has a tendency to _________ if it is moving and a tendency to _________ if it is at rest. This is called __________. I know it would keep rolling forever unless a force acts on it because it is stated by __________. If friction and air resistance were removed from the “real world”, the ball would __________. A football is thrown and __________.

PTG (p143) a) The ball will __________ b) because __________. If the vertical height on the left is 20cm, then the vertical height on the right is __________. __________ and __________ would have to be removed from the “real world” in order for an object to remain in a straight line at a constant speed forever. A hockey puck on ice will__________ until a external force acts on it.