worksheet_06.doc

6 Worksheet (AS) v

A body moving with speed v collides elastically with another body travelling in

1

the opposite direction with speed

v

2

v

2

.

Which row in the table below correctly gives the relative velocity of approach and the relative velocity of separation of the two bodies? Relative velocity of approach A B C D

v

v

2

2

v

3v

2

2

3v

v

2

2

3v

3v

2

2

Fina Finall vel veloc ocit ity y v v 1." v 1." v

A B C D

Loss Loss in kine kineti ticc ene energ rgy y 2 mv 3mv2 mv2 3mv2

#n an inelastic collision which $!antities are conserved? A B C D

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Relative velocity of  separation

A body of mass m travels with a velocity 3 v and collides with another particle of mass 2 m which is initially stationary. After the collision, the two particles move with the sa me velocity. Which row in the table gives the final velocity of the two particles and the loss in inetic energy d!ring the collision? [1]

2

3

[1]

total inetic energy and total moment!m b!t not total energy total inetic energy and total energy b!t not total moment!m total moment!m and total energy b!t not total inetic energy total inetic energy, total moment!m and total energy

A particle has moment!m  p1 at time t 1 and moment!m  p2 at time t 2. What is the average force acting on the particle between t 1 and t 2? A

  p +  p        t  t  +       p −  p        t  t  −       p  p + %."    t  t    p  p + %."  t  t    1

2

2

1

2

C

1

1

1

D

[1]

2

1

B

[1]

2

2

A& and A 'evel (hysics

2

2

1

1

               

)riginal material * +ambridge niversity (ress 2%1%

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6 Worksheet (AS)

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What is a correct statement of the principle of conservation of moment!m? A B C D

6



[1]

in an inelastic collision the total inetic energy and moment!m are constant in any collision the total moment!m of an isolated system is constant in any isolated system the force on a body e$!als the rate of change of moment!m moment!m is constant when mass and velocity are constant

A b!mper-car b!mper-car collides at right angles with a metal barrier and rebo!nds at the same s ame speed. A st!dent s!ggests that the change in moment!m of the car is ero. /0plain why the st!dent is wrong.

[2]

/ach diagram shows a 2.% g obect before and after a collision. +alc!late the change in moment!m of the obect in each case.

a

[2]

!

[2] c

[2] "

A cannon of mass "% g fires a 2% g shell at a velocity of 1% m s 1. a ! c

#

+alc!late the final moment!m of the shell. What is the magnit!de of the moment!m of the cannon immediately after the shell is fired? 45o! 45o! may ass!me that the cannon is initially at rest.6 +alc!late the recoil velocity V  of  o f the cannon.

[2] [2] [3]

A car of mass 7%% g travelling at a velocity of 2 m s 1 maes a head-on collision with a stationary van of mass 1"%% g. 8he car and the van get tangled together. a ! c

+alc +alc!l !lat atee the the comb combin ined ed spee speed d of of the the tang tangle led d veh vehicl icles es imme immedi diat ately ely afte afterr the the coll collis isio ion. n. +alc!late the initial inetic energy of the car and the final inetic energy of the tangled car and van immediately after the collision. se yo!r answer to ! to  to e0plain whether the collision is elastic or inelastic.

A& and A 'evel (hysics

)riginal material * +ambridge niversity (ress 2%1%

[9] [9] [3] [1]

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6 Worksheet (AS)

1$ 8he diagram below shows the initial state of two trolleys A and B before colliding and the final state immediately after the collision.

+alc!late the final velocity v of trolley B.

[9]

11 8he diagram shows two toy trains % and R  held  held in place on a level trac against the force e0erted  by a compressed spring.

When the trains are released, R  moves  moves to the right at a speed of 3. m s 1. 8he spring taes %.2" s to !ncoil to its nat!ral length. a !

+alc!late the velocity of train %. +alc!late the average force e0erted by the spring on each train.

[9] [9]

12 A ball of mass 21% g moving at a speed of 23 m s 1 hits a wall at right angles and rebo!nds at the same speed. 8he ball is in contact with the wal l for %.31 s. a ! c

+alc!late the change in moment!m of the ball. #s the moment!m of the !all co  conserved? /0plain yo!r answer. +alc!late the magnit!de of the average force acting on the ball.

A& and A 'evel (hysics

)riginal material * +ambridge niversity (ress 2%1%

[2] [2] [3]

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6 Worksheet (AS)

13 8he diagram below shows the initial state of two identical balls A and : before collision and the final state immediately after the collision. 8he mass of each ball is 1.2 g.

:efore the collision, the velocity of A is 3.% m s 1 and B is stationary. A maes an obli$!e collision with B. After the collision, A moves off at an angle of 3%; to its original direction and has a velocit y of 2.< m s 1. B is deflected at an angle θ  with  with a velocity of 1." m s 1. a !

/0plain why the final moment!m of the system in a direction at right angles to the initial velocity of A is ero. =ence determine the angle θ .

[3]

&how that the total moment!m of the system is conserved.

[3] 8otal>

A& and A 'evel (hysics

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&core>

)riginal material * +ambridge niversity (ress 2%1%

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