2points
an athlete jumps with a speed of 4 m/s at an angle of 23º. how long does the
athlete stay in the air?
o a. 0.32 s
o b. 0.925
o c. 0.55 s
o d. 0.75 s

A. 0.32s

Explanation:

Lets find the initial velocity of the vertical component

Cos23=u/4

4cos23=1.6m/s

then time, t =2u/g

2×1.6/9.8

=0.32seconds

A. 0.32 s

Explanation:

The other answer did the math wrong but came up with the same answer. Anyway, you're supposed to use sin.

4sin(23) gives you 1.56 or 1.6

-1.56/-9.8 (negative because gravity is working against the direction of of the athlete as he goes into the air) = 0.159...

0.159*2 = 0.318

Round: 0.32

grav potential energy

the skeletons of most mammals reach a certain size and then stop growing. however, many animals, including some mammals, keep growing throughout their lives. kangaroos, for example, just keep growing and growing until they die. also, the longer an animal lives the greater the chance it might catch some deadly disease.