Projectile Motion
Projectile Motion
Projectile Motion
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10/6/2008<br />
MOMENTUM<br />
MOMENTUM<br />
Momentum refers to the quantity<br />
of motion that an object has.<br />
Momentum = mass x velocity<br />
All objects have mass; so if an<br />
object is moving, then it has<br />
momentum –<br />
it has its mass in motion.<br />
The amount of momentum which<br />
an object has is dependent upon<br />
two variables: how much (mass) stuff<br />
is moving and how fast (velocity) the<br />
stuff is moving.<br />
p = mv<br />
• Momentum is a vector quantity.<br />
• As a vector quantity, the momentum<br />
of an object is fully described by<br />
both magnitude and direction.<br />
MOMENTUM<br />
CHECK YOUR UNDERSTANDING<br />
<br />
From the definition of momentum,<br />
it becomes obvious that an object<br />
has a large momentum if either its<br />
mass or its velocity is large.<br />
Consider a truck and a scooter<br />
moving down the street at the<br />
same speed. The considerably<br />
greater mass of the truck gives it a<br />
considerably greater momentum.<br />
Yet if the truck were at rest, then<br />
the momentum of the scooter<br />
would be the greatest.<br />
1. Determine the momentum of a ...<br />
a) 60-kg halfback moving east at 9 m/s.<br />
b) 1000-kg car moving north at 20 m/s.<br />
c) 40-kg student moving south at 2 m/s.<br />
2. A car possesses 20 000 units of<br />
momentum. What would be the car's<br />
new momentum if ...<br />
a) its velocity were doubled.<br />
b) its mass were doubled (by adding<br />
more passengers and a greater load)<br />
MOMENTUM<br />
Law of Conservation of Momentum -<br />
momentum will be transferred from object to<br />
another.<br />
MOMENTUM ANIMATION<br />
Before the collision, the momentum of the cart ______<br />
and the momentum of the brick is ______; the total<br />
system momentum is _______. After the collision, the<br />
momentum of the cart is _______ and the momentum of<br />
the dropped brick is _______; the total system<br />
momentum is _______.<br />
The momentum of the system is conserved.<br />
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10/6/2008<br />
IMPULSE<br />
REAL WORLD APPLICATION<br />
Impulse = Change in momentum<br />
In a collision, objects experience an impulse; the<br />
impulse causes (and is equal to) the change in<br />
momentum.<br />
Consider a collision of a tennis ball with a wall.<br />
CHECK YOUR UNDERSTANDING<br />
Complete Practice Problems<br />
http://www.glenbrook.k12.il.us/gbssci/Phys/Class/momentum/u4l1a.html<br />
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