F = 130 revs/min = 130/60 revs/s = 13/6 revs/s
t = 31s
wi = 2πf = 2π × 13/6 = 13π/3 rads/s
wf = 0 rads/s = wi + at
a = -wi/t = -13π/3 × 1/31 = -13π/93 rads/s²
wf² - wi² = 2a∅
-169π²/9 rads²/s² = 2 × -13π/93 rads/s² × ∅
∅ = 1209π/18 rads
n = ∅/2π = (1209π/18)/(2π) = 1209/36 ≈ 33.5833 revolutions.
Answer:
$4.2
Explanation:
Given data
Power= 700W
time= 10 hours
Cost per kilowatt hours is cents $0.20
Let us find the number of hours in a month
=24*30
=720 hours
Energ= power*time
Energy= 700/1000*30
Energy= 7*3
Enery= 21 kwh
1 kwh= 0.2
21kwh= x
cross multiply
x=21*0.2
x= $4.2
Answer:
R2 = 300 Ohms
Explanation:
Let the two resistors be R1 and R2 respectively.
RT is the total equivalent resistance.
Given the following data;
R1 = 100 Ohms
RT = 75 Ohms
To find R2;
Mathematically, the total equivalent resistance of resistors connected in parallel is given by the formula;

Substituting into the formula, we have;

Cross-multiplying, we have;
75 * (100 + R2) = 100R2
7500 + 75R2 = 100R2
7500 = 100R2 - 75R2
7500 = 25R2
R2 = 7500/25
R2 = 300 Ohms
Given values:
Mass of the steel ball, m = 100 g = 0.1 kg
Height of the steel ball, h1 = 1.8 m
Rebound height, h2 = 1.25 m
a. PE= mgh
0.1 x 9.8 x 1.8 =
1.764 Joules
b. KE = PE ->
1.764 Joules
c. KE= 1/2 mv square
so v = square root 2ke/m
square root 2 x 1.764/ 0.1
= 5.93 m/s
d. KE=PE=mgh square
0.1 x 9.8 x 1.21 =
1.186 joules
velocity of rebond is square root 2x 1.186/ 0.1 = 4.87 m/s