Let the width be x, then length = 4x - 7
Perimeter = 2(length + width)
2(x + 4x - 7) = 46
2(5x - 7) = 46
10x - 14 = 46
10x = 60
x = 6
Therefore, width is 6 and length is 4(6) - 7 = 24 - 7 = 17
Write the equation as such and narrow down x value being 4
The answer to this question is B) 44.78
Answer:
- KEi = 2.256×10^5 J
- KEf = 9.023×10^5 J
- 4 times as much work
Step-by-step explanation:
The kinetic energy for a given mass and velocity is ...
KE = (1/2)mv^2 . . . . . m is mass
At its initial speed, the kinetic energy of the car is ...
KEi = (1/2)(810 kg)(23.6 m/s)^2 ≈ 2.256×10^5 J . . . . . m is meters
At its final speed, the kinetic energy of the car is ...
KEf = (1/2)(810 kg)(47.2 m/s)^2 ≈ 9.023×10^5 J
The ratio of final to initial kinetic energy is ...
(9.023×10^5)/(2.256×10^5) = 4
4 times as much work must be done to stop the car.
_____
You know this without computing the kinetic energy. KE is proportional to the square of speed, so when the speed doubles, the KE is multiplied by 2^2 = 4.
Answer:
I think it is C.
Step-by-step explanation:
Really hope it helps
