Momentum
•Momentum is the amount of m
•Momentum is to do with the m
of an object
an object has
and the v
•In an explosion the momentum of an object moving
to the l
is equal to the
of the object
which moves to the r
Fill in the answers and then click to check them
otion an object has
•Momentum is the amount of m_____
assand the v______
•Momentum is to do with the m___
elocity
of an object
•In an explosion the momentum of an object moving
to the l____
__________ of the object
eft is equal to the momentum
which moves to the r_____
ight
is the amount of motion an object has
TUM NO MEM
is measured in Newtons
RE COF
is how fast it moves in a certain direction
CITY OF VEL
the amount of material measured in kilograms
SAMS
the unit for velocity
STREEM ERP DESCON
the unit for mass
OG RI SMALK
POXLESION
when stationary objects go in opposite directions
old fashioned gun
NO NANC
spherical object leaving the previous gun
LALB
modern gun which you rest on the shoulder to fire
LE RIF
fired by the gun above
TUBLLE
Fill in the answers and then click to check them
is the amount of motion an object has
momentum
is measured in Newtons
force
is how fast it moves in a certain direction
velocity
the amount of material measured in kilograms
mass
the unit for velocity
Metres per second
the unit for mass
kilograms
explosion
when stationary objects go in opposite directions
old fashioned gun
cannon
spherical object leaving the previous gun
ball
modern gun which you rest on the shoulder to fire
rifle
fired by the gun above
bullet
Fill in the answers and then click to check them
Calculating momentum
How much momentum do the following object have?
1 A 700kg car travelling at 10 m/s
Momentum =
x
=
2 A 1500kg van travelling at 5m/s
Momentum =
x
=
3 A mini travelling at 20m/s with a mass of 800kg
Momentum =
x
=
4 A 45kg person running at 4m/s
Momentum =
=
x
click for the answers
How much momentum do the following object have?
1 A 700kg car travelling at 10 m/s
Momentum =
700
x
10
= 7000 kgm/s
2 A 1500kg van travelling at 5m/s
Momentum =
1500 x 5
= 7500 kgm/s
3 A mini travelling at 20m/s with a mass of 800kg
Momentum =
800
x
20
= 16 000 kgm/s
4 A 45kg person running at 4m/s
Momentum =
45
x 4
= 180 kgm/s
Explosions
cannonball moves this way
with a high velocity
Cannon moves this way more slowly
as it recoils from the explosion
Velocity as it leaves the cannon = 400m/s
Mass of cannon ball =?
Momentum
of ball
= Momentum of
cannon
mass x velocity = mass x velocity
of the ball
of the cannon
? X 400 = 100 x 8
? X 400 = 800
? = 800/400 = 2kg
Recoil velocity = 8m/s
Mass = 100kg
Now do your own calculation
Fill in the answers and then click to check them
Velocity as it leaves the cannon = 500m/s
Mass of cannon ball =?
V
Momentum
of ball
= Momentum of
cannon
mass x velocity = mass x velocity
of the ball
of the cannon
?x
?x
?=
=
=
x
=
Recoil velocity = 10m/s
Mass = 50kg
Velocity as it leaves the cannon = 500m/s
Mass of cannon ball =?
Momentum
of ball
= Momentum of
cannon
mass x velocity = mass x velocity
of the ball
of the cannon
? X 500 = 50 x 10
? X 500 = 500
? = 500/500 = 1kg
Recoil velocity = 10m/s
Mass = 50kg
Collisions
•The moving ball hits the stationary ball
•The stationary ball moves off
•If the first ball stops
•The second ball gains all the momentum of the first ball
v
2m/s
5kg
5kg
Momentum of first ball = momentum of second ball
(before collision)
(after collision)
5kg x 2m/s = 5kg x v
So v = 2m/s
In the second case the first ball has more mass but the same idea applies
Momentum of first ball = momentum of second ball
(before collision)
(after collision)
8kg x 2m/s = 4kg x v
So v = 4m/s
v
2m/s
4kg
8kg
Now try these
v
3m/s
12kg
12kg
Momentum of first ball = momentum of second ball
(before collision)
(after collision)
x
So v =
=
xv
In the second case the first ball has more mass but the same idea applies
Momentum of first ball = momentum of second ball
(before collision)
(after collision)
x
So v =
Now click for
the answers
=
xv
v
5m/s
4kg
12kg
Now try these
v
3m/s
12kg
12kg
Momentum of first ball = momentum of second ball
(before collision)
(after collision)
12 x 3 = 12 x v
So v = 3m/s
In the second case the first ball has more mass but the same idea applies
Momentum of first ball = momentum of second ball
(before collision)
(after collision)
12 x 5
=
So v = 15m/s
4 xv
v
5m/s
4kg
12kg
More collisions
Higher level
Momentum before the collision
(of the single ball)
= Momentum after the collision
( of both balls)
Momentum before the collision
(of the single ball)
= Momentum after the collision
( of both balls)
3 x 8 = (3+3) v
24 = 6 x v
So v = 24/6
v = 4m/s
v
3kg
8 m/s
3kg
3kg
Another example
Momentum before the collision
(of the single ball)
= Momentum after the collision
( of both balls)
3 x 9 = (6+3) v
27 = 9 x v
So v = 27/9
v = 3m/s
V
6kg
9 m/s
3kg
3kg
Now try this one yourself
Momentum before the collision
(of the single ball)
= Momentum after the collision
( of both balls)
=
x
=
xv
xv
So v =
Click for the answer
V
1kg
10 m/s
4kg
4kg
Momentum before the collision
(of the single ball)
= Momentum after the collision
( of both balls)
3 x 9 = (6+3) v
27 = 9 x v
V = 3m/s
V
6kg
9 m/s
3kg
3kg
Collisions and safety
Higher level
Stopping quickly is dangerous because
a large force is felt for a short time
The crumple zone on this car allows the
car to change shape slowly so that a
smaller force is felt for a longer time
Hitting the windscreen in a car crash means that a
large force is felt for a short time which can
cause severe injuries for the driver
Hitting the airbag in a car crash means that a
smaller force is felt for a longer time which is
Much safer for the driver
Force
(N)
Which line represents
the air bag?
The blue line
The red line shows a big force
for a short time
The blue line shows a smaller force
acting over a longer time
time
(s)