2D Momentum Problem with little info for Object

[aeromat]

2D Momentum Problem with little info for Object

Homework Statement

A 0.150kg billiard ball [A] is rolling toward a stationary billiard ball at 10.0m/s. After the collision, ball [A] rolls off at 7.7m/s at an angle of 40.0 degrees clockwise from its original direction. What is the speed and direction of ball B after the collision?

Homework Equations

Conservation of Momentum
(Assuming I don't know the conservation of kinetic energy yet, or stuff about elastic/inelastic collisions)

The Attempt at a Solution

Ok, basically I got any INFO I would need regarding [A], but yet I have no idea how to approach

X-component[MAVA + 0 = MAV'A + MBV'B]
Y-component[0 = MAV'A + MBV'B]

X [(0.150kg)(10.0m/s) + 0 = (0.150kg)(7.7cos[40]m/s) + MBV'B]
Y [0 = (0.150kg)(-7.7sin[40]m/s) + MBV'B)]

I don't have a clue as to how I will solve for the velocity, when I am lacking any info on mass..

 

[SammyS]

Conservation of momentum is all that's needed. Remember: momentum is a vector quantity.

The equations you show can be solved for the x and y components of the momentum of ball B.

 

[WatermelonPig]

(mb)(vb)sin(theta) = (0.150)(7.7)sin(40)

(mb)(vb)cos(theta) = (0.150)(10) - (0.150)(7.7)cos(40)

Divide the first equation by the second and you should get tan(theta) = some number so you can solve for theta.

 

[Chronos]

The deflection angle and velocity of B is all you need to deduce the mass of A, given it is stationary. Deducing velocity and incident angle of A is simple once you have the mass.

 

[DR>Taeps]

a 0.2kg block is sliding along a smooth horizontal surface at 8m/s. a bullet is fired at right angles to its motion and remains embeded in the block. if the impact changed direction of the block's motion by 30 degrees whatis the bullet's speed just before it struck the block?