Question

quem entende de física pode me ajudar, por favor? ​

Answer 1

1)v = 54 km/h = 15 m/s

m = 6 kg

$E_{c}=\frac{m.v^{2}}{2}\\\\E_{c}=\frac{6.15^{2}}{2}\\\\E_{c}=\frac{6.225}{2}\\\\E_{c}=\frac{3}{225}\\\\E_{c}=675 \ J$

2)m=7kg

v = 90 km/h = 25 m/s

v0 = 36 km/h = 10 m/s

$T = \Delta E_{c}\\\\T = \frac{m.v^{2}}{2} - \frac{m.v_{0}^{2}}{2}\\\\T = \frac{7.25^{2}}{2} - \frac{7.10^{2}}{2}\\\\T = \frac{7.625}{2} - \frac{7.100}{2}\\\\T = \frac{4375}{2}-\frac{700}{2}\\\\T = \frac{3675}{2}\\\\T = 1837,5 \ J$

3)g = 10 m/s^2

h = 12 m

m = 25 kg

$E_{pg}=m.g.h\\\\E_{pg}=25.10.12\\\\E_{pg}=3000 \ J$

4)k = 300 N/m

x = 2 cm = 2.10^-2 m

$E_{pe} = \frac{k.x^{2}}{2}\\\\E_{pe} = \frac{300.(2.10^{-2})^{2}}{2}\\\\E_{pe} = \frac{300.4.10^{-4}}{2}\\\\E_{pe} = 300.2.10^{-4}\\E_{pe} = 600.10^{-4}\\\\E_{pe} = 6.10^{-2} \ J$