Two automobiles of equal mass approach an intersection. One vehicle is traveling with velocity 12.0 m/s toward the east and the other is traveling north with speed v2i. Neither driver sees the other. The vehicles collide in the intersection and stick together, leaving parallel skid marks at an angle of 64.5° north of east. Determine the initial speed v2i of the northward-moving vehicle.

25.7m/s

Explanation: the cars have equal masses so we only consider their velocities,

The cars traveled together at 65° north of east this is with a velocity equal to the resultant velocity,

Using the force diagram as shown below;

Tan 65° = Vn/Ve

Ve is velocity of the car traveling east

Vn is velocity of car traveling north

Tan 65° = V2/12

2.144 = V2/12

V2 = 12 * 2.144

V2 = 25.7 m/s

the answer is to check all of them! they all apply well at least i think so!

at positions a, g kinetic energy is maximum.

at position d, potential energy is maximum.