Question

16.) a marathon runner runs at a constant speed of 13 miles per hour. when she approaches a turn on the track to change direction. what variable is changing? a.) heat b.) velocity c.) gravity d.) spikes 17.) short answer: a.) what does the 1st law of motion state and give me a real - life example. b.) give an example of the 3rd law of motion and include an example of either an elastic or inelastic collision. extra credit: the kicker has made contact with the football. in order for the ball to follow the path shown by the dotted line, what must be true of the forces acting on the ball? a) force 1 must be the greatest. b) force 2 must be the greatest. c) force 3 must be the greatest. d) force 4 must be the greatest

Explanation:

Step1: Analyze question 16

Speed is constant but direction changes. Velocity is speed with direction, so velocity changes.

Step2: Analyze Newton's 1st Law for question 17A

Newton's 1st Law (Law of Inertia) states an object at rest stays at rest and an object in motion stays in motion with a constant velocity unless acted upon by an external force. Example: A book on a table stays still until someone pushes it.

Step3: Analyze Newton's 3rd Law for question 17B

Newton's 3rd Law states for every action, there is an equal and opposite reaction. For an elastic - collision example, when two billiard balls collide, they bounce off each other with the same total kinetic energy conserved.

Step4: Analyze extra - credit question

The ball is moving in the direction of the net force. To follow the upward - curved path, the vertical force (Force 2) must be significant to counter - act gravity and give it an upward trajectory. So Force 2 must be the greatest.

Answer:

1. B. Velocity

17A. Newton's 1st Law (Law of Inertia) states an object at rest stays at rest and an object in motion stays in motion with a constant velocity unless acted upon by an external force. Example: A book on a table stays still until someone pushes it.
17B. Newton's 3rd Law states for every action, there is an equal and opposite reaction. Elastic - collision example: When two billiard balls collide, they bounce off each other with the same total kinetic energy conserved.
Extra Credit. B. Force 2 must be the greatest.