JEE Main & Advanced Physics Work, Energy, Power & Collision / कार्य, ऊर्जा और शक्ति Sample Paper Topic Test - Work Energy Power

  • question_answer
    A uniform rectangular marble slab is 3.4 m long and 2.0 m wide. It has a mass of 180 kg. If it is originally lying on the flat ground, how much work is needed to stand it on an end?

    A) 2.0 kJ

    B) 3.0 J

    C) 3.0 kJ

    D) 3000 kJ

    Correct Answer: C

    Solution :

    [c] The work done by gravity is the work done, as if all the mass were concentrated at the centre of mass.   The work necessary to lift the object can be thought of as the work done against gravity and is just\[W=mgh\], where h is the height through which the centre of mass is raised.   \[W=180\left( 9.8 \right)\text{ }\left( 1.7 \right)=\text{ }3.0\text{ }kJ\]

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