1) 1/2 m V^2 = 12.5W2) 1/2mV'^2 = 1/2mV^2 + mgh => v' = 根号(V^2+2gh) = 15 m/s
1/2 m V^2 = 12.5W2) 1/2mV'^2 = 1/2mV^2 + mgh => v' = 根号(V^2+2gh) = 15 m/s
1题:W=1/2MV*V=12.5J2题:15m/s