Problem 7.30 A 0.26-kg block is held in place against the spring by a 28-N horiz
ID: 1775034 • Letter: P
Question
Problem 7.30 A 0.26-kg block is held in place against the spring by a 28-N horizontal external force (see the figure). The external force is removed, and the block is projected with a velocity v 1 = 1.2 m/s upon separation from the spring. The block descends a ramp and has a velocity v 2= 1.6 m/s at the bottom. The track is frictionless between points A and B. The block enters a rough section at B, extending to E. The coefficient of kinetic friction over this section is 02. The velocity of the block is v 3 -1.4 m/s at C. The block moves on to D, where it stops. The initial compression of the spring is closest to: Part A V1 VA V2 smooth BoughEExplanation / Answer
Data needed for the initial compression.
F = k*x = 28 N
v1 = 1.2 m/s
m = 0.26 kg
Now we know
½*m*v12 = ½*k*x2
x = (mv12)/kx
put the value of m, v1 and kx
x = (0.26*1.22)/28
x = 0.0133714 m
x = 1.3 cm