Which of the following is an example of Newton’s first law of motion? Sam’s bike hits a curb and he flies over the handlebars, onto the grass.
A feather and a brick are dropped from a ladder. The brick exerts a greater force when it hits the ground.
A person sits on a chair and pushes down, and the chair pushes upwards on the person.
Tires from a car push against the road, and the road pushes back.

You have two photos of a person walking. one shows the person at the corner of third and main streets, the other shows the person at the corner of tenth and main streets. there are lampposts at every corner in this town, and the first picture shows it to be 10: 32: 00 exactly. the second picture shows it to be 10: 49: 30. you know three facts: (1) all of the clocks are synchronized; (2) there are exactly 12 equal-sized blocks per kilometer in this town; and (3) the streets that cross main in this area are numbered consecutively, with no interruptions. what is the person’s average speed in kilometers per hour?