Question

Suppose a car experienced a head-on collision in Cartoon world. (in the calculation, round to nearest integer)

1. Before the collision, the mass of the car is 1500kg, and the speed is 36km/hr, and the car is going to the north. What is its momentum? Is its momentum a vector? If it is a vector, indicate it's direction and magnitude. (We can define the north as the positive direction in the following calculation)

2. There is a truck heading south, but the driver falls into sleeping and hit the car head to head. The mass of the truck is 1500 kg, and the speed is 3.6km/hr. What is the truck's momentum?

3. However, the collision still happened at last. But a miracle happened, no people or vehicle got hurt or damaged, and no energy loss in the collision, they just change their velocity. After the collision, the car has a motion to south with speed as 3.6km/hr. What is the change of the car's momentum during the collision? (be careful of the direction )

4. If we can average the force which applied to the car in the collision, what is the impulse of the force?

5. We assume the collision time is 0.1s, and we can average the force, what is the average force?

6. Actually, the force hit the car should be a changing force, let us assume the left graph in the figure on Page 71 is its force-time graph, which equation can I use to find the impulse of the force? (Just write down the equation)

7. What will the prediction look like?

Answer 1

1.

Yes, it is a vector whose magnitude is 15000 kgm/s and direction is to the north.

2.

Because it points to the south, we can write it

3.

(To the south)

4.

5.

6.

(Graph is not shown)