Term
| linear momentum of an object is defined as |
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Definition
The linear momentum 'p' of an object :
is the product of its mass & a velocity
ex. a faster & heavy truck has MORE momentum than a small moving car
aka it takes MORE force to stop the truck than the car. |
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Term
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Definition
→ →
p = m v
where :
p : momentum (a vector)
v: velocity (m/s)
m: mass (kg) |
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Term
Momentum is a vector and points in the _____ direction as the _______ vector. |
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Definition
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Term
One can also say that the momentum vector is _______ to the velocity vector,
if the momentum vector ______ if the velocity vector doubles. |
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Definition
| directly proportional, doubles |
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Term
| A _____ is required to increase, decrease, or change the direction of momentum |
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Definition
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Term
| relate momnetum to Newton's second law |
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Definition
| the rate of change of momnetum of an object is equal to the net force applied to it. |
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Term
| Give equation that relates momentum to Newton's second law |
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Definition
ΣF=Δp/Δt
sum of forces= change in mommentum/change in time
same as
ΣF=p final - p inital/Δt
same as
ΣF=mv2- mv1/Δt |
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Term
| Momentum is a ______ quality |
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Definition
conserved,
momentum is same before and after a collsion etc..
'the total momemtum of an isolated system of objects remains CONSTANT |
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Term
| Equation for conservation of momentum (such as 2 objects colliding) |
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Definition
| mA vA + mB vB = mA vA + mB vB |
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Term
| In a given system, momentum will always be conserved if _____ |
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Definition
no external forces are present
ex. friction, gravity |
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Term
Conceptual Example 7-5:
An empty sled is sliding on frictionless ice when Riley drops vertically from a tree above onto the sled. When she lands, does the sled speed up, slow down, or keep same speed?
B. What happens if Riley falls sideways off the slide? |
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Definition
A. Speed decreases
fall vertically: no inital horizontal momentum, so the total horizontal momentum is equal to the momentum of sled intinally.
b/c sled has more mass, the speed decreases
B. SAME speed b/c momentum is conserved |
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Term
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Definition
impulse (Δp) =
force • Δt
unit: Newtons/ seconds |
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Term
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Definition
| is equal to the total change in momentum |
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Term
| a collision in which the total kinetic energy is called an |
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Definition
elastic collision
KEf= KEi |
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Term
| give equation for a totally elastic collision |
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Definition
1/2m1v1+1/2m2v2=1/2m1v'1 + 1/2 m2v'2
where v' is velocity after collision
(recall ke is 1/2 mv) |
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Term
| Give equation for v'1 in elastic collision |
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Definition
| v'1 = (m1-m2/ m1 + m2) x V1 |
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Term
| collisions in which kinetic energy is NOT conserved is called? |
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Definition
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Term
| In a totally elastic collision what happens to the objects |
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Definition
| they collide & go off in seperate directions |
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Term
| In a totally inelastic collision what happens to the objects |
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Definition
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Term
- In a totally inelastic collision what is conserved?
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Definition
momentum & ofcourse TOTAL energy as always
*energy not created or destroyed |
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Term
| Give equation for inelastic collision |
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Definition
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Term
Give components of theta for:
x axis
y axis
flat & incline |
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Definition
FLAT
X: cosθ
y: sinθ
INCLINE
X:sinθ
Y:cosθ |
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