Final answer:
To determine the net force and whether kinetic energy will increase or decrease, vector addition of the sled dog force and the wind force is needed. After calculating the components of each force and summing them, the magnitude of the net force can be used to ascertain changes in kinetic energy.
Step-by-step explanation:
The question involves calculating the net force acting on a sled during the Iditarod race. To find the net force, we need to consider both the force exerted by the sled dogs and the force of the wind. The sled dogs are exerting a force of 1200 N in the direction of travel, while the wind exerts a force of 300 N at a 135-degree angle to the direction of travel.
Since these forces are acting at an angle to one another, we need to use vector addition to determine the net force. The horizontal component of the wind's force can be found by multiplying the wind's force by the cosine of 135 degrees (which gives us a negative value since it's directed opposite to the sled's motion), and the vertical component can be found by multiplying the wind's force by the sine of 135 degrees.
After calculating these components, they are added to the force exerted by the dogs. Since the wind's horizontal component is opposite the dogs' force, it will subtract from the 1200 N force. However, the vertical component has no opposing force, so it adds to the net force on the sled. After adding the vectors, we can use the Pythagorean theorem to find the magnitude of the net force.
If the net force is in the direction of travel, the kinetic energy of the sled will increase, and if it is against the direction of travel, the kinetic energy will decrease. Given the forces are not equal and opposite, the net force will not be zero, and thus there will be a change in kinetic energy.