A 5000 kg helicopter accelerates upward at 0.6 m/s2 while lifting a 1500 kg car. a) What is the lift force supplied by the helicopter rotors? b) What is the tension in the cable connecting the car to the helicopter? Answer:a) 67600 N b)15600 N How do I get these?Thanks.
(a) Fnetacceleration*mass(6510kg+1180kg). FnetFa-FwFa-mg FaFnet+mg4614N+(6510kg+1180kg)*9.8m/. 8.0*10^4 N --answer (b) Fnet on the motor vehicle1180kg*.6m/s^2708N Fnetfeet-Fw feetFw+Fnet1180kg*9.8m/s^2+708N a million.2*10^4 N
F ma is your baby here. For the first one, how much weight must the rotors lift? They must lift the weight of the car and the helicopter right? So we add them together. 5000kg + 1500kg 6500kg total that the rotors must lift. We know that the acceleration due to gravity is 9.81m/s2, but the helicopter is accelerating upwards at 0.6m/s2. If its accelerating up, its making the load feel like its heavier than it really is. So we add the accelerations. 9.81 + 0.6 10.41m/s2. Now just substitute into F ma F 6500kg * 10.41m/s2 67665 N For B, the tension in the cable would just be the force of the car right? Cuz the cable is only holding the car up. So again F ma F 1500kg * 10.41m/s2 15615N
the slight difference may be the fact that the gravity given to you was 9.8 m/s^2 instead the 9.81 he used
