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A-body-is-projected-at-an-angle-35-with-an-initial-speed-of-45m-s-What-is-the-velocity-of-the-body-after-2s-and-the-angle-made-with-the-horizontal-axis-g-9-81ms-2-




Question Number 31148 by NECx last updated on 03/Mar/18
A body is projected at an angle  35° with an initial speed of 45m/s.  What is the velocity of the body  after 2s and the angle made with  the horizontal axis? [g=9.81ms^(−2) ]
Abodyisprojectedatanangle35°withaninitialspeedof45m/s.Whatisthevelocityofthebodyafter2sandtheanglemadewiththehorizontalaxis?[g=9.81ms2]
Commented by NECx last updated on 03/Mar/18
for the velocity in time t, we have   V(t)=usin θ−gt  v(2)=45sin35 − 9.81×2      =25.81094−19.62       =6.19m/s    then I got confused on seeing angle  made with the horizontal.Please  help. Thanks
forthevelocityintimet,wehaveV(t)=usinθgtv(2)=45sin359.81×2=25.8109419.62=6.19m/sthenIgotconfusedonseeinganglemadewiththehorizontal.Pleasehelp.Thanks
Answered by mrW2 last updated on 03/Mar/18
u=45 m/s  u_x =45 cos 35°  u_y =45 sin 35°  v_x (t)=u_x   v_y (t)=u_y −gt  v(t)=(√(v_x ^2 +v_y ^2 ))  tan θ(t)=(v_y /v_x )  θ(t)=tan^(−1) ((v_y /v_x ))    at t=2 s:  v_x (2)=45 cos 35°=36.86 m/s  v_y (2)=45 sin 35°−9.81×2=6.19 m/s  v(2)=(√(36.86^2 +6.19^2 ))=37.4 m/s  θ(2)=tan^(−1) ((6.19)/(36.86))=9.5°
u=45m/sux=45cos35°uy=45sin35°vx(t)=uxvy(t)=uygtv(t)=vx2+vy2tanθ(t)=vyvxθ(t)=tan1(vyvx)att=2s:vx(2)=45cos35°=36.86m/svy(2)=45sin35°9.81×2=6.19m/sv(2)=36.862+6.192=37.4m/sθ(2)=tan16.1936.86=9.5°
Commented by NECx last updated on 03/Mar/18
thank you so much sir
thankyousomuchsir

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