Calculate the electrical energy supplied to the motor during this time

A motor having an efficiency of 0.8 uses 800 J of electrical energy. The output energy of the motor is:

The input power to a motor is 12W. The motor wastes 590 J of energy in 1.0 min. What is the efficiency of the motor?

17 The total energy supplied to an electric motor is E. Energy Q is wasted and the remaining energydoes useful work.What is the efficiency of the motor?A QE B QE    – 1 C 1 – QE    D (1 )QE

A 400V dc. motor develops a shaft torque of 150Nm at 3000 rev/min. If the efficiency is83%, determine the current supplied to the motor.

17 A motor is used to lift a load vertically upwards.The load has weight W.The motor produces useful power output P.The load is lifted at constant velocity v.Which expression gives the time taken for the motor to lift the load vertically upwards through adistance d ?A WdP B PWv C PWd D WPv18 A lamp is switched on for 2.0 hours. The power input to the lamp is 1.0 W. The energy given outby the lamp as light is 7.0  10 3 J.How much energy is converted to other forms by the lamp?A 120 J B 200 J C 3400 J D 7200 J19 An object of mass m is dropped onto the surface of two planets, X and Y, which have noatmosphere.The height from which the object is dropped and the change in gravitational potential energy ofthe object, for each planet, are given in the table.height / m change in gravitationalpotential energyplanet X 3 ∆Eplanet Y 4 4∆EThe acceleration of free fall near the surface of planet X is gX .What is the acceleration of free fall near the surface of planet Y?A X43 g B X34 g C 3gX D 4gX20 A known tensile force acts on a metal wire. The wire does not exceed its limit of proportionality.Which two measurements enable the strain of the wire to be calculated?A the unstretched length of the wire and the cross-sectional area of the wireB the unstretched length of the wire and the extension of the wireC the Young modulus of the metal and the extension of the wireD the Young modulus of the metal and the unstretched length of the wire