Ahorizontal clothesline is tied between 2 poles, 12 meters apart. when a mass of 4 kilograms is tied to the middle of the clothesline, it sags a distance of 5 meters. what is the magnitude of the tension on the ends of the clothesline?

Space-time metric ds2= -dt2+at2dx2+bt2dy2+ct2dz2 (a)how does the area of a rectangle with vertices at ( x=0, y=0, z=0 ), (1,0,0 ), ( 0,1,0 ) and (1,1,0 ) changes with time? (b) if a photon moving in the x direction starts from the origin at t=1, when does it reach x=l? (ds=0 for the trajectory of a photon.) (c) the proper time for a particle is defined by cd=ds. what is the proper time for a particle to move along the trajectory ( x(t)=t, y(t)=0, z(t)=0 ) from t=0 to 1 ? what is the condition on the parameter a so that the velocity of the particle never exceeds the speed of light ?

An object moves from position +34m to the position -15m in 15 seconds. what is the total displacement? what is the total velocity?

What are the north and south poles of a solenoid change with?