Jack is practicing prior to a football tryout. He wants to work on his speed and agility, so he practices running forward the length of a football field and then running backwards the length of a football field. When he runs forward, he can run 100 yards in 10 seconds. When he is running backward, he can run 100 yards in 20 seconds. What is his speed when he is running backward? 1) 10yd/sec
2) -5yd/sec
3) -10 yd/sec
4) 5 yd/sec

colorectal cancer may also develop from areas of abnormal cells in the lining of the colon or rectum. this area of abnormal cells is called dysplasia and is more commonly seen in people with certain inflammatory diseases of the bowel such as crohn's disease or ulcerative colitis.

anchor = archer //

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.