SPH 4U
2D Collision Problems
Answer these questions using complete solutions including
 Designated direction(s)
 Vectors
 Formulae
 units
1.
A grenade of mass 1.20 kg is at rest on a smooth, frictionless surface when it
suddenly explodes into three pieces. A 0.50 kg piece flies off horizontally to the
north at 3.0 m/s, and a 0.30 kg piece flies off horizontally to the southwest at 4.0
m/s. What is the horizontal speed and direction of the third piece? (2.7 m/s [E37˚S])
2.
Repeat the above problem, but this time assume that the grenade was moving at a
constant velocity of 1.5 m/s [E] just before it exploded. (Assume that the final
speeds and directions of pieces one and two remain the same.) (6.8 m/s [E14°S])
3.
A bomb initially at rest on a smooth, horizontal surface is exploded into three pieces.
Two pieces fly off horizontally at a 60°angle to each other, a 2.0 kg piece at 20 m/s
and a 3.0 kg piece at 12 m/s. The third piece flies off horizontally at 30 m/s.
(a) Determine the direction of motion of the third piece. (148° CCW from the 3.0 kg piece)
(b) What is its mass? (2.2 kg)
4.
A 2000 kg car travelling east at 24 m/s enters an icy intersection and collides with a
3600 kg truck travelling south at 10 m/s. If they become coupled together in the
collision, what is their velocity immediately after impact? (11 m/s [E37˚S])
5.
A nucleus, initially at rest, decays radioactively. In the process, it emits an electron
horizontally to the east, with momentum 9.0 x 10-21 kg●m/s and a neutrino
horizontally to the south, with momentum 4.8 x 10-21 kg●m/s.
(a) In what direction does the residual nucleus move? (W28˚N)
(b) What is the magnitude of its momentum? (1.0 x 10-20 kg●m/s)
(c) If the mass of the residual nucleus is 3.6 x 10-25 kg, what is its recoil velocity?
(2.8 x 104 m/s)
6.
A steel ball of mass 0.50 kg, moving with a velocity 2.0 m/s, strikes a second ball of
mass 0.30 kg, initially at rest. The collision is a glancing one, causing the first ball to
be deflected by an angle of 30°, with a speed of 1.50 m/s. Determine the velocity of
the second ball after the collision, giving both its speed and direction. (1.7 m/s [R47°D])
7.
A 3000 kg space capsule is travelling in outer space with a velocity of 200 m/s. In an
effort to alter its course, it fires a 25.0 kg projectile perpendicular to its original
direction of motion at a speed of 2000 m/s. What is the new speed of the space
capsule? By what angle has its direction changed? (2.02 x 102 m/s, 4.76°)
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