Respuesta :
Answer:
(a) The kinetic energy in joules is 194400 J
(b) The energy in calories is 46462.72 calories
(c) When the automobile brakes to a stop, the energy will decrease to 0 J.
Explanation:
(a) Kinetic energy (K.E) is given by the formula below
[tex]K.E = \frac{1}{2}mv^{2}[/tex]
Where K.E is the kinetic energy in Joules (J)
[tex]m[/tex] is the mass in kilogram (kg)
[tex]v[/tex] is the velocity in meter per second (m/s)
From the question,
[tex]m =[/tex] 1200 kg
[tex]v =[/tex] 18 m/s
Hence,
[tex]K.E = \frac{1}{2}mv^{2}[/tex] becomes
[tex]K.E = \frac{1}{2}(1200)(18)^{2}\\K.E = (600)(324)\\[/tex]
[tex]K.E = 194400[/tex] J
This is the energy is joules
(b) To convert this energy to calories (cal)
4.184 J = 1 cal
Then, 194400 J = [tex]x[/tex] cal
[tex]x = \frac{194400 \times 1}{4.184}[/tex]
[tex]x = 46462.72[/tex] cal
K.E = 46462.72 calories
This is the energy in calories
(c) When the automobile brakes to a stop, the energy will decrease to 0 J.
