Object Motion: 25 m/s
Circumference of Circle:
1/4 Circumference of Circle in 1 second = 25 meters
25 meters times 4 = Circumference of Circle
Circumference = 100 meters
Formula to Find Circumference of Circle: (work opposite)
C = 2<span>πr
100 = </span>2πr divided
100/2π = r simplify
50/π = r (exact radius)
Answer:
50/π meters = r (exact radius)
The time after being ejected is the boulder moving at a speed 20.7 m/s upward is 2.0204 s.
<h3>What is the time after being ejected is the boulder moving at a speed 20.7 m/s upward?</h3>
The motion of the boulder is a uniformly accelerated motion, with constant acceleration
a = g = -9.8 
downward (acceleration due to gravity).
By using Suvat equation:
v = u + at
where: v is the velocity at time t
u = 40.0 m/s is the initial velocity
a = g = -9.8
is the acceleration
To find the time t at which the velocity is v = 20.7 m/s
Therefore,

The time after being ejected is the boulder moving at a speed 20.7 m/s upward is 2.0204 s.
The complete question is:
A large boulder is ejected vertically upward from a volcano with an initial speed of 40.0 m/s. Ignore air resistance. At what time after being ejected is the boulder moving at 20.7 m/s upward?
To learn more about uniformly accelerated motion refer to:
brainly.com/question/14669575
#SPJ4
Answer:
Image will form at distance 22.22 cm behind the mirror
Explanation:
As we know that the mirror formula is given as

now we know that
object distance from mirror is

Focal length of the mirror is given as

now we have



Human error (average human reaction time is .2 seconds)