A 45000 pound truck is travelling at 5 mph. It hits a stationary object that is fixed in place. What is the force exerted on the object?

To determine the force exerted on the object, you need to use Newton's second law of motion, which states that force is equal to mass multiplied by acceleration.

First, we have the mass of the truck, which is given as 45000 pounds.

To convert this mass from pounds to a more commonly used unit like kilograms, we need to know the conversion factor. 1 pound is approximately 0.4536 kilograms. Multiplying the truck's mass by this conversion factor, we find that the truck's mass is approximately 20411.65 kilograms.

Next, we need to calculate the acceleration of the truck when it hits the stationary object. As the truck is initially moving at 5 mph (miles per hour), we need to convert this velocity to meters per second, which is the standard unit for acceleration.

To convert from miles per hour to meters per second, we use the conversion factor of 0.44704. Multiplying the initial speed of 5 mph by this conversion factor, we find that the truck's speed is approximately 2.2352 meters per second.

Since the truck hits the stationary object, its final velocity becomes zero. Therefore, the change in velocity is the final velocity minus the initial velocity. In this case, 0 minus 2.2352 meters per second equals -2.2352 meters per second.

Now we can calculate the force using Newton's second law of motion:

Force = mass x acceleration

Force = 20411.65 kg x -2.2352 m/s^2

When we multiply these two values together, we find that the force exerted on the object by the truck is approximately -45568.50768 Newtons.

Note: The negative sign indicates that the force exerted on the object is in the opposite direction to the truck's initial motion.