\"Relative\" is an important word. In the figure below, block L of mass m L = 2.
ID: 2244287 • Letter: #
Question
"Relative" is an important word. In the figure below, block L of mass mL = 2.00 kg and blockR of mass mR = 0.500 kg are held in place with a compressed spring between them. When the blocks are released, the spring sends them sliding across a frictionless floor. (The spring has negligible mass and falls to the floor after the blocks leave it.)
"Relative" is an important word. In the figure below, block L of mass mL = 2.00 kg and blockR of mass mR = 0.500 kg are held in place with a compressed spring between them. When the blocks are released, the spring sends them sliding across a frictionless floor. (The spring has negligible mass and falls to the floor after the blocks leave it.) If the spring gives block L a release speed of 1.40 m/s relative to the floor, how far does block R travel in the next 0.800 s? If, instead, the spring gives block L a release speed of 1.40 m/s relative to the velocity that the spring gives blockR, how far does block R travel in the next 0.800 s?Explanation / Answer
using conservation of momentum we can find velocity of block R as (ml)*(vl)/(mr)
vr=1.4*2/0.5
vr = 5.6 m/s
distance travelled by block R in 0.8 s = 5.6*8 = 44.8 m-------------------------------(a)
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let x be the velocity of block R in the opp dirn
given relative velocity of block L = 1.4 m/s
therefore actual velocity of block L = 1.4-x
again using conservation of momentum we have ml*vl = mr*vr
(1.4-x)*2 = x*0.5
2.8 = 2.5x
x= 1.12 m/s
distance travelled in 0.8 s = 1.12*0.8= 0.896 m
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