A particle of mass 100 g is thrown vertically upwards with a speed of 5 ms^(-1). The work done by the force of gravity during the time the particle goes up is

A particle of mass 100 g is thrown vertically upwards with a speed of

1.	A particle of mass 100 g is thrown vertically upwards with a speed of 5 ms^(-1). The work done by the force of gravity during the time the particle goes up is
Answer» `-0.5J` `-1.25J` `1.25 J` `0.5 J` SOLUTION :The height (h) TRAVERSED by particle while going up is `h = (u^2)/(2g) = (25)/(2 xx 9.8)""….(i)` The force of gravity (= mg) is opposite to the displacment . So the work done by the force of gravity is `W = - mgh = -0.1 xx 9.8 xx 25/(2 xx 9.8)"(USING (i))"` ` = -0.1 xx 25/2 = -1.25 J`