1. 
(10m - 14) + 9 = 12 1. Given
2. 5m - 7 + 9 = 12 2. Distributive Property
3. 5m + 2 = 12 3. Simplify (added like terms)
4. 5m = 10 4. Subtraction Property of Equality
5. m = 2 5. Division Property of Equality
"Will is twice as old as Jill."
Jill's age . . . . . J
Will's age . . . . 2J .
"Three years ago . . .
Jill's age then . . . . . J - 3
Will's age then . . . . 2J - 3
". . . Jill's age then was 2/5 of Will's age then."
J - 3 = (2/5) (2J - 3)
Multiply
each side by 5 : 5J - 15 = 2 (2J - 3)
Divide
each side by 2 : 2.5 J - 7.5 = 2J - 3
Subtract 2J
from each side: 0.5 J - 7.5 = -3
Add 7.5
to each side: 0.5 J = 4.5
Multiply
each side by 2 : J = 9
Jill is 9 y.o. now.
Will is 18 y.o. now.
Answer:
6.
Step-by-step explanation:
1) OA=d/2=20/2=10;
2) AB=AC/2=16/2=8;
When the car is moving, it has Kinetic Energy. As soon as the car entercount with the spring, its Kinetic Energy will transfer to Elastic Potential Energy.
<span>KE = EPE </span>
<span>1/2mv^2 = 1/2kx^2 </span>
<span>change the speed into m/s </span>
<span>50 km/hr = 13.9 m/s </span>
<span>1/2(1200)(13.9)^2 = 1/2k(2.2)^2 </span>
<span>now you do the math to solve for k.
k= 115926/2.42
K= 47903.30</span>
