Mark sees a crushed soda can on the ground. He kicks it fiercely with a velocity of 12m/s at projected angle of 36°. What is the highest point that the soda can reaches? Sin 36 degrees equals 0.866. 2. A 5000 kg. freight train traveling at speed of 28 m/s strikes an identical car at rest. If they stick
Solution.
"1. v_0=12ms^{-1};"
"\\alpha =36^o;"
"h_{max}-?;"
"v=0ms^{-1};"
"v_{0y}=v_0\\sdot sin \\alpha;" "v_{0y}=12ms^{-1}\\sdot0.866=10.392ms^{-1};"
"h_{max}=\\dfrac{v_y^2-v_{0y}^2}{2g};"
"h_{max}=\\dfrac{0m^2s^{-2}-108m^2s^{-2}}{-2\\sdot9.8ms^{-2}}=5.51m" ;
"2. m=5000kg;"
"v_1=28ms^{-1};"
"v_2=0ms^{-1};"
"m_1=m_2=m;"
"mv_1+mv_2=(m_1+m_2)v_F" ;
"v_F=\\dfrac{mv_1+mv_2}{m_1+m_2};"
"v_F=\\dfrac{5000kg\\sdot28ms^{-1}+5000kg\\sdot0ms^{-1}}{5000kg+5000kg}=14ms^{-1};"
Answer: "1. h_{max}=5.51m;\n2. v_F=14ms^{-1}."
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