Example #1: 2D Collisions

Example #2: 2D Collisions

Two bags of sand are sliding on a horizontal frictionless surface. Bag A has mass 2.0 kg and bag B has mass 5.0 kg. Initially bag A is traveling east with speed vAi and bag B is traveling south with speed vBi.The two bags collide and after the collision bag A is sliding at 1.50 m/s in a direction 30.0° north of east and bag B is sliding at 2.50 m/s in a direction 37.0° south of east. What was the initial speed of each bag?

On a horizontal frictionless surface block A (mass 2.00 kg) is sliding toward the east with speed vAi and block B (mass 4.00 kg) is sliding north at speed vBi. The blocks collide and stick together. After the collision the combined object (mass 6.00 kg) is moving at 36.9° north of east at vf = 8.00 m/s.
What was the initial speed vAi of block A?

On a horizontal frictionless surface block A (mass 2.00 kg) is sliding toward the east with speed vAi and block B (mass 4.00 kg) is sliding north at speed vBi. The blocks collide and stick together. After the collision the combined object (mass 6.00 kg) is moving at 36.9° north of east at vf = 8.00 m/s.
What was the initial speed vBi of block B?

On a horizontal frictionless surface block A (mass 3.00 kg) is sliding toward the east with speed VA and Block B (mass 5.00kg) is sliding toward the north with speed VB. After the collision block B is sliding toward the north with speed 2.00 m/s and block A is sliding with a speed of 6.00 m/s in a direction of 30.0° north of east, as shown in the sketch. What are the speeds VA and VB of the two blocks before the collision?
Ans. VA =
Ans. VB =

A rock with mass 2.0 kg is at rest on a horizontal frictionless surface. A bullet with mass 0.100 kg is traveling due east with a speed of 400 m/s just before it strikes the rock. Just after the collision between the bullet and the rock, the bullet is moving south with a speed of 300 m/s. What is the speed of the rock just after the collision with the bullet?
A) 5.0 m/s
B) 15.0 m/s
C) 25.0 m/s
D) 59.2 m/s
E) None of the above answers

A neutron collides elastically with a helium nucleus (at rest initially) whose mass is four times that of the neutron. The helium nucleus is observed to move off at an angle of 45°. The neutrons initial speed is 5.1×105 m/s{
m {
m m/s}}.(a) Determine the speeds of the two particles, vn and vHe, after the collision.(b) Determine the angle of the neutron after the collision.

An object with an initial momentum represented by the vector below, strikes an object that is initially at rest. Which of the following sets of vectors may represent the momenta of the two objects after the collision? Note carefully: The original vector below and the following vectors are ALL DRAWN TO THE SAME LENGTH SCALE.

Two asteroids of equal mass in the asteroid belt between Mars and Jupiter collide with a glancing blow. Asteroid Aexttip{A}{A}, which was initially traveling at vA1 = 40.0 m/s with respect to an inertial frame in which asteroid was at rest, is deflected 30.0° from its original direction, while asteroid B exttip{B}{B}travels at 45.0° ^circ to the original direction of Aexttip{A}{A}, as shown in the figure.(a) Find the speed of asteroid A after the collision.(b) Find the speed of asteroid B after the collision.(c) What fraction of the original kinetic energy of asteroid exttip{A}{A} dissipates during this collision?

Two ice skaters, Daniel (mass 70.0 kg) and Rebecca (mass 45.0 kg), are practicing. Daniel stops to tie his shoelace and, while at rest, is struck by Rebecca, who is moving at 14.0 m/s before she collides with him. After the collision, Rebecca has a velocity of magnitude 8.00 m/s at an angle of 54.1° from her initial direction. Both skaters move on the frictionless, horizontal surface of the rink.(a) What is the magnitude of Daniels velocity after the collision?(b) What is the direction of Daniels velocity after the collision?(c) What is the change in total kinetic energy of the two skaters as a result of the collision?

A stone with mass 0.800 kg rests on a horizontal frictionless surface. A bullet with mass 0.0200 kg traveling horizontally at speed VAi strikes the stone and rebounds horizontally at a speed of VAf in an direction perpendicular to its original motion. After being hit by the bullet, the stone is moving at 6.00 m/s in a direction 30.0° from the original direction of motion of the bullet. What are the speeds VAi and VAf of the bullet before and after the collosion?Ans. VAi = VAf =

A(n) 7 kg object moving with a speed of 6.5 m/s collides with a(n) 18 kg object moving with a velocity of 8.2 m/s in a direction 21° from the initial direction of motion of the 7 kg object. What is the speed of the two objects after the collision if they remain stuck together?
1. 9.10604
2. 7.63104
3. 8.34111
4. 9.58276
5. 7.78221
6. 9.34713
7. 8.24562
8. 6.89647
9. 9.73592
10. 10.3766

On a horizontal frictionless surface block A (mass 4.0 kg) is sliding toward the east with a speed of 6.0 m/s and block B (mass 8.0 kg) is sliding toward the north with a speed of 9.0 m/s. The blocks collide. Immediately after the collision block A is sliding toward the north with speed 7.0 m/s and block B is sliding with a speed of VBf at an angle θ north of east. Calculate the speed VBf and the angle θ.Ans. VBf = Ans. θ =

A particle with mass m moving at speed v collides with a particle with mass 2m initially at rest. After the collision, the two particles have velocities that are directed at equal angles of θ on either side of the original line of motion of the m particle. What is the speed v' of the 2m particle after the collision?
1. v' = v/4sinθ
2. v' = v/cosθ
3. v' = vsinθ/4
4. v' = v/4cosθ
5. v' = vcosθ
6. v' = v/2cosθ
7. v' = vsinθ/2
8. v' = v/sinθ
9. v' = vcosθ4