If c is the curve given by r(t)=(1+2sint)i+(1+3sin2t)j+(1+1sin 3t)k, 0≤t≤π2 and f is the radial vector field f(x, y,z)=xi+yj+zk, compute the work done by f on a particle moving along c.

Under the action of a constant force an object accelerates at 7.8 m/s2. what will the acceleration be if (a) the force is halved? (b) the object's mass is halved? (c) the force and the object's mass are both halved? (d) the force is halved and the object's mass is doubled?