A block of mass M = 3.1 kg is at rest on an incline (θ = 27°) that has friction between the incline’s surface and the base of the block. The block sits a distance L from the bottom of the incline. Attached to the block is a stretched spring (i.e., L Xo ) that has a spring constant k = 24 N/m and a natural length of Xo = 2.5 meters. Suppose the magnitude of the frictional force acting on the block is Ffr = 18 Newtons. Use g = 9.81 m/s2.

Question

A block of mass M = 3.1 kg is at rest on an incline (θ = 27°) that has friction between the incline’s surface and the base of the block. The block sits a distance L from the bottom of the incline. Attached to the block is a stretched spring (i.e., L > Xo ) that has a spring constant k = 24 N/m and a natural length of Xo = 2.5 meters. Suppose the magnitude of the frictional force acting on the block is Ffr = 18 Newtons. Use g = 9.81 m/s2.

anonymous · Answer

What is Fs , the magnitude of the spring force acting on the block?

anonymous · Answer

I understand its Ff - mgsin(theta) but that comes out to be negative. I dont know where I am going wrong