Recent content by wwmertww

A man lifts a 20-kg box from the ground up to the top of a 30-m high building. The box is initially at rest, but it travels at 4 m/s when it reaches the top of the building. How much work is done by the man in lifting the box? A. 5840 J B. 160 J C. 2400 J D. 6000 J E. 6160 J answer is still...

F= m.a W= F.d use thıs two fırst to get the value K=1/2 M v^2 and add thıs one f=20x(9,8)=196N w=196.20=3920N k=1/2.20.(4^2)=160N we should add thıs two value because final velocity of the partıcle is 4 m/s. answer=160+3920N=4080N solving by FUAT MERT AĞARLI