What Went Wrong in Calculating the Velocity of Carts C and B After Collision?

P=mv) and the conservation of momentum (Pfinal=Pinitial), we get the same result of 8.5 m/s. So it seems like the answer of 7.8 m/s is incorrect.
  • #1
jacegalvin
2
0

Homework Statement

:
A cart 'C' mass of 2 tonnes is launched at 10m/s towards Cart 'B' which is 3 tonnes and moving at 12.5m/s. The angle between their paths of motion is 90 degrees. When the 2 carts collide, they remain stuck together. what is the velocity of the stuck together cart 'CB'
assuming no friction.


Homework Equations


P=mv
Pfinal=Pinitial
c= √b2+c2



The Attempt at a Solution



what i assumed was you could create a right angle triangle, with momentum of Cart C as one side, momentum of Cart B as another and the hypotenuse would be momentum of cart CB

So therefore:
Pbc= √Pb2+Pc2
Pbc=√(3000x12.5)2+(2000x10)2
Pbc=√1406250000+400000000
Pbc=4250
Pbc=m(c+b)v
4250=5000v
v=8.5m/s

but apparently the answer is 7.8m/s
what have i done wrong?
 
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  • #2
the answer must be 8.5 m/s, i got the same by using vectors.
 
  • #3
8.5 seems correct
 

1. What is an inelastic collision?

An inelastic collision is a type of collision in which the objects involved stick together after impact, resulting in a loss of kinetic energy. This is in contrast to an elastic collision, where the objects bounce off each other with no loss of energy.

2. How is momentum conserved in a 2d inelastic collision?

In a 2d inelastic collision, momentum is conserved in both the x and y directions. This means that the total momentum before the collision is equal to the total momentum after the collision in both the horizontal and vertical directions.

3. What is the equation for calculating the final velocities in a 2d inelastic collision?

The equation for calculating the final velocities in a 2d inelastic collision is vfx = (m1v1x + m2v2x) / (m1 + m2) and vfy = (m1v1y + m2v2y) / (m1 + m2), where m1 and m2 are the masses of the objects and v1x, v1y, v2x, and v2y are the initial velocities in the x and y directions.

4. What is the coefficient of restitution in an inelastic collision?

The coefficient of restitution is a measure of the elasticity of a collision. In an inelastic collision, the coefficient of restitution is less than 1, indicating that there is a loss of kinetic energy.

5. How does the angle of impact affect the final velocities in a 2d inelastic collision?

The angle of impact does not affect the final velocities in a 2d inelastic collision. The final velocities are only determined by the masses and initial velocities of the objects involved.

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