A person is sitting on a sled and someone is about to push them down a hill. Which statement is accurate?
1: Forces acting on the sled are paired with unequal and opposite forces.
2: Forces acting on the sled are paired with the force of gravity only.
3: Forces acting on the sled are paired with equal and opposite forces.
4: Forces acting on the sled are paired with the force of friction only.

Ineed the answer to question 1 , i’m desperate

If the chemical properties of a substance remain unchanged and appearance or shape of a substance changes it is called a ?

Arunner is jogging at a steady 3.6 km/hr. when the runner is 2.9 km from the finish line, a bird begins flying from the runner to the finish line at 14.4 km/hr (4 times as fast as the runner). when the bird reaches the finish line, it turns around and flies back to the runner. even though the bird is a dodo, we will assume that it occupies only one point in space, i.e., a zero-length bird. how far does the bird travel? (b) after this first encounter, the bird then turns around and flies from the runner back to the finish line, turns around again and flies back to the runner. the bird repeats the back and forth trips until the runner reaches the finish line. how far does the bird travel from the beginning? (i.e. include the distance traveled to the first encounter)