Momentum - two cars crashing at an angle

In summary, the problem involves a collision between a 2000 kg car and a 1200 kg car, resulting in the 1200 kg car moving at 40.00 km/h @ 35(deg) N of E. By applying the equation MV(before) = MV(after) and taking into account the momentum in the X and Y directions, the velocity of the 2000 kg car can be determined to be 81.2 km/h before the collision.
  • #1
XxphysicsxX
22
0
:cry:

Homework Statement



A 2000 kg car strikes a staitionary 1200 kg car and rebounds at 65.0 km/h@ 20 (deg) Sof E. After collision, the 1200 kg car moves at 40.00 km/h @ 35(deg) N of E. Determine the velocity of the 2000 kg car before the collision.

m1= 2000 kg
V1(before) = ?
V1(after) = 18.05 m/s

M2= 1200 kg
V2(before) = 0 m/s
V2 (after) = 11.11 m/s


Homework Equations


MV(before) = MV(after)
Momentum.


The Attempt at a Solution



In the X direction:
momentum of object 1 (before)= M1V1a + M2V2a - M2V2b
= (2000)(18.5)(cos 70) + (1200)(11.11)(cos 35) - (0)
= 23267. 855
In the Y direction
momentum of object 1 (before)= M1V1a + M2V2a - M2V2b
= (2000)(18.05)(sin 70) + (1200)(11.11)(sin 35)
= 41569.82

C^2 = A^2 + B^2
C =ROOT [(23267. 855^2) + (41569.82 ^2)]
C = 47638.67 = momentum

momentum / mass = velocity
47638.67 / 2000 kg = 23.81 m/s

23.81 m/s= 85.71 km/h <<<<<<<<<<<< which is wrong... its supposed to be 81.2 km/h

... and i don't get the right angle either.

Ive been at this for two days any help will be greatly appretiated
 
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  • #2
You have a mistake in the y direction; missing a minus sign on one of the mv's. One is north, the other south. Then partially cancel, reducing the answer. It works out to 81.2 for me.

Probably not a good idea to convert to m/s since the question and the answer are in km/hr.
 
  • #3
thankyou so muchhh!
 

1. What is momentum and how is it related to two cars crashing at an angle?

Momentum is a measure of an object's motion, and it is directly related to the mass and velocity of the object. When two cars crash at an angle, their momentum is combined and the resulting momentum will determine the direction and speed of the combined objects after the collision.

2. How does the angle of impact affect the momentum of the cars in a collision?

The angle of impact can significantly affect the momentum of the cars in a collision. When the cars collide head-on, their momentum will be directly combined. However, if the cars collide at an angle, their momentum will be combined in a more complex way, with some components being added and others being subtracted. This can result in a different final momentum for the combined objects.

3. What factors can impact the momentum of two cars in a collision?

The mass and velocity of the cars, as well as the angle of impact, are the main factors that can impact the momentum of two cars in a collision. The mass and velocity of each car will determine its individual momentum, while the angle of impact will affect the combined momentum of the cars.

4. How can we calculate the momentum of two cars in a collision?

To calculate the momentum of two cars in a collision, we need to know the mass and velocity of each car before the collision, as well as the angle of impact. The total momentum can then be calculated by adding the individual momentums of the cars, taking into account the direction and angle of impact.

5. Is momentum conserved in a two-car collision at an angle?

Yes, momentum is always conserved in any collision, including a two-car collision at an angle. This means that the total momentum of the two cars before the collision will be equal to the total momentum of the combined objects after the collision, regardless of the angle of impact or any other factors.

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