9th Class Science Work and energy Question Bank 9th CBSE Science Work and energy

  • question_answer
      Figure shows a conveyor belt                           Conveyor belt transporting a 'package to a   raised platform. The belt is driven by a motor.               (i)State three types of energy, other than gravitational potential energy, into which the electrical energy supplied to the motor is converted. (ii) The mass of the package is 36 kg. Calculate the increase in the gravitational potential energy (p.e.) of the package when it is raised through a vertical height of 2.4 m. (iii) The package is raised through the vertical height of 2.4 m in 4.4 s. Calculate the power needed to raise the package. (iv) Assume that the power available to raise package is constant. A package of mass greater than 36 kg is raised through the same height. Suggest and explain the effect of this increase in mass on the operation of the belt.  

    Answer:

                      (i) (a) Kinetic energy of belt or the package. (b) Heat energy                                (c) Sound energy (ii) m = 36 kg, h = 2.4 m, g = 10 m/s2 Gravitational potential energy= mgh = 36 x 10 x 2.4 = 864 J (iii) Power   Mass is increased and power is constant, so increase in potential energy of mass is greater. Also, as mass is increased, speed is reduced and hence time taken is longer.


You need to login to perform this action.
You will be redirected in 3 sec spinner