Answer:
the speed of ball = 1 mile per second
<h3> or</h3>
1 mile / sec
Step-by-step explanation:
cuz speed = distance ÷ time
so speed of ball = 1 mile ÷ 1 sec = 1 mile / sec
There are two (equivalent) formulas for the circumference of a circle:
C = 2 pi r, where r is the radius of the circle
C = pi d, where d is the diameter of the circle
In this particular problem, however, we're dealing with arc length. For the shown central angle "theta" = 160 degrees, the arc length is 42 cm.
Knowing this enables us to calculate the radius or diameter of the circle.
Arc length = s = (radius) (central angle, in radians, not degrees)
First, convert 160 degrees to radians: 160 deg pi rad
----------- * ------------ = (8/9) pi rad
1 180 deg
Then 42 cm = r *(8/9) pi rad
Solve for the radius (r): divide 42 cm by (8/9) pi rad
Then use the formula for circumference introduced earlier:
C= 2 pi r Substitute [42 cm / ( (8/9) pi rad )] for r.
Simplify your result, and you will then have the circumference, C, in cm.
Answer:
x = - 5/2 or x = - 3/2
Step-by-step explanation:
|-2(x+2|=1
|-2x-4|=1
- 2x - 4 = 1 or - 2x - 4 = - 1
- 2x - 4 = 1
- 2x = 4+1
x = - 5/2
or -2x - 4 = - 1
-2x = 4 - 1
x = - 3/2
You do distance over time to get the rate, so you'd do 27/2= 13.5mph then divide that in half since you're asking for the distance traveled in half that hour so you do 13.5/2 and you get 6.75 miles traveled in half and hour.
Before the driver applies the brakes ( with the reaction time ):
d 1 = v0 · t = 20 m/s · 0.53 s = 10.6 m
After that:
v = v0 - a · t1
0 = 20 m/s - 7 · t1
7 · t1 = 20
t1 = 2.86 s
d 2 = v 0 · t1 - a · t1² / 2
d 2 = 20 m/s · 2.86 s - 7 m/s² · (2.86 s)²/2 = 57.2 m - 28.6 m = 28.6 m
d = d 1 + d 2 = 10.6 m + 28.6 m = 39.2 m
Answer: the stopping distance of a car is 39.2 m.
