At what speed would a 1140-kg car have the same momentum as a 12,600-kg truck traveling at 25 km/hr?

The hint given to this problem is that I need to find the velocity of the car and truck.
Converting 25 km/hr to m/s I get 6.944 m/s as the initial velocity.. The professor told us that the velocity should be 15 for the truck. How is the professor getting this number???

Your conversion is correct.

The Prof errs.

To find the velocity of the truck, we can convert the given speed of 25 km/hr to meters per second (m/s).

To convert km/hr to m/s, we multiply by a conversion factor of (1000 m / 1 km) divided by (3600 s / 1 hr).

So, we have:
(25 km/hr) * (1000 m / 1 km) * (1 hr / 3600 s) = 6.944 m/s (rounded to three decimal places)

Therefore, you are correct in converting the truck's speed to 6.944 m/s.

However, it seems like there might be confusion regarding the professor's solution. Without further information, it's hard to determine how the professor arrived at a velocity of 15 for the truck.

In the given problem, we are trying to find the velocity of the car that would result in the same momentum as the truck. To solve this, we can use the principle of conservation of momentum, which states that the total momentum before a collision is equal to the total momentum after the collision.

The momentum of an object is given by the product of its mass and velocity. So, we can write the equation as follows:

(mass of car)(velocity of car) = (mass of truck)(velocity of truck)

Plugging in the given values, we have:

(1140 kg)(velocity of car) = (12600 kg)(6.944 m/s)

Simplifying the equation:

velocity of car = (12600 kg)(6.944 m/s) / 1140 kg

Evaluating the expression gives us the velocity of the car that would result in the same momentum as the truck.