As shown in the figure, a 1.45-kg block is held in place against the spring by a 21-N horizontal external force. The external force is removed, and the block is projected with a velocity $v_ \mathrm { 1 } = 1.2 \mathrm {~m} / \mathrm { s }$ as it separates from the spring. The block descends a ramp and has a velocity $v_ 2 = 2.1 \mathrm {~m} / \mathrm { s }$ 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 between the block and the rough surface is 0.29. The velocity of the block is $v_ 3 = 1.4 \mathrm {~m} / \mathrm { s }$ at C. The block moves on to D, where it stops. How much work is done by friction between points B and C?
A)-1.8 J
B)-3.6 J
C)-14 J
D)-6.4 J
E)-7.0 J

Question

As shown in the figure, a 1.45-kg block is held in place against the spring by a 21-N horizontal external force. The external force is removed, and the block is projected with a velocity $v_ \mathrm { 1 } = 1.2 \mathrm {~m} / \mathrm { s }$ as it separates from the spring. The block descends a ramp and has a velocity $v_ 2 = 2.1 \mathrm {~m} / \mathrm { s }$ 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 between the block and the rough surface is 0.29. The velocity of the block is $v_ 3 = 1.4 \mathrm {~m} / \mathrm { s }$ at C. The block moves on to D, where it stops. How much work is done by friction between points B and C? 
A)-1.8 J 
B)-3.6 J 
C)-14 J 
D)-6.4 J 
E)-7.0 J

Quizplus · Accepted Answer

The Answer of As shown in the figure, a 1.45-kg block is held in place against the spring by a 21-N horizontal external force. The external force is removed, and the block is projected with a velocity $v_ \mathrm { 1 } = 1.2 \mathrm {~m} / \mathrm { s }$ as it separates from the spring. The block descends a ramp and has a velocity $v_ 2 = 2.1 \mathrm {~m} / \mathrm { s }$ 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 between the block and the rough surface is 0.29. The velocity of the block is $v_ 3 = 1.4 \mathrm {~m} / \mathrm { s }$ at C. The block moves on to D, where it stops. How much work is done by friction between points B and C? 
A)-1.8 J 
B)-3.6 J 
C)-14 J 
D)-6.4 J 
E)-7.0 J

As Shown in the Figure, a 1 v1=1.2 m/sv_ \mathrm { 1 } = 1.2 \mathrm {~m} / \mathrm { s }v1​=1.2 m/s

As Shown in the Figure, a 1 $v_ \mathrm { 1 } = 1.2 \mathrm {~m} / \mathrm { s }$