Question
An elevator is rising at constand speed. Consider thefollowing statements: I. The upward cable force is constant II. The kinetic energy of the elevator is constant III. The gravitational potential energy of the Earth-elevatorsystem is constant IV. the acceleration of the elevator is zero V. the mechanical energy of the earth-elevator system isconstant A)all five are true B)only II and V are true C)only IV and V are true D)only I,II, III are true E)only I,II, and IV are true An elevator is rising at constand speed. Consider thefollowing statements: I. The upward cable force is constant II. The kinetic energy of the elevator is constant III. The gravitational potential energy of the Earth-elevatorsystem is constant IV. the acceleration of the elevator is zero V. the mechanical energy of the earth-elevator system isconstant A)all five are true B)only II and V are true C)only IV and V are true D)only I,II, III are true E)only I,II, and IV are true
Explanation / Answer
An elevator is rising at constand speed. Consider thefollowing statements: I. The upward cableforce is constant II. The kinetic energyof the elevator is constant III. The gravitational potential energy of the Earth-elevatorsystem is constant NOT TRUE... it is increasing because ofincreasing height IV. the acceleration ofthe elevator is zero V. the mechanical energy of the earth-elevator system isconstant NOT TRUE... mech energy includespotential energy, which is changing A)all five are true B)only II and V are true C)only IV and V are true D)only I,II, III are true E)only I,II, and IV aretrue CORRECT ANSWER