On an icy road, a 1100 kg car moving at 55 km/h strikes a 480 kg truck moving in the same direction at 37 km/h . The pair is soon hit from behind by a 1300 kg car speeding at 49 km/h. If all three vehicles stick together, what is the speed ofthe wreckage?

Speed of the wreckage = 49.29 km/hr

Explanation:

This question is solved simply by using the conservation of momentum law.

The momentum of the three moving bodies are calculated below:

Momentum of Car 1 : 1100 * 55 = 60500 kg.km/hr

Momentum of Truck : 480 * 37 = 17760 kg.km/hr

Momentum of Car 2 : 1300 * 49 = 63700 kg.km/hr

Total mass of all three vehicles: 1100 + 480 + 1300 = 2880 kg

The final momentum equals the initial momentum if it is conserved. Thus we have the following equation:

Final Momentum = Initial Momentum

Final Velocity * Total mass = Momentum of all three vehicles combined

Final Velocity * 2880 = 60500 + 17760 + 63700

Final Velocity = 49.29 km/hr

radial fractures in a piece of glass look most like which of the following?

a. spokes of a wheel

b. a circle

c. a zig zag

d. none of the above

the correct answer is a. spokes of a wheel

hope this (: