関連ワード:  define work class 9 physics    what is work class 9 physics    define work done class 9 physics    what is work class nine physics    define 1j of work class 9 physics    what is work done class 9 physics    what is zero work class 9 physics    what is negative work class 9 physics    what is work according to class 9th physics    define work in physics class 9 with example