Question

me ayudan con los ejercicios ?​

Answer 1

Respuesta:

1.- m = 16 kg

2.- Ec = 4 900 000 J

3.- v = 14.14 m/s

Explicación:

1.-

$Ec = \frac{1}{2} mv {}^{2} \\ m = \frac{2Ec}{v {}^{2} } \\ m = \frac{2(450J)}{(7.5 \frac{m}{s} ) {}^{2} } \\ m = \frac{900J}{56.25 \frac{m {}^{2} }{s {}^{2} } } \\ m = 16 \: kg$

2.-

$Ec = \frac{1}{2} mv {}^{2} \\ Ec = \frac{1}{2} (2000 kg)(70 \frac{m}{s} ) {}^{2} \\ Ec = \frac{1}{2} (2000kg)(4900 \frac{m {}^{2} }{s {}^{2} } ) \\ Ec = \frac{1}{2} (9 \: 800 \: 000J) \\ Ec =4 \: 900 \: 000J = 4 \: 900 \: kJ$

3.-

$Ec = \frac{1}{2} mv {}^{2} \\ v {}^{2} = \frac{2Ec}{m} \\ v = \sqrt{\frac{2Ec}{m} } \\ v = \sqrt{ \frac{2(1500J)}{15kg} } \\ v = \sqrt{ \frac{3000J}{15kg} } \\ v = \sqrt{200 \frac{m {}^{2} }{s {}^{2} } } \\ v = 14.14 \frac{m}{s}$