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15. A body of mass 5kg starts from the origin with an initial velocity u = 30î +40 jms.If a constant force F =-(+5j)N acts onthe body, the time in which the y - compo-nent of the velocity becomes zero is2) 20s 3) 40s 4) 80s211) 55 |
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Answer» ere, mass of the BODY , m=5kg; y-component of INITIAL velocity, uy=40m/s and y-component of the force, Fy=−5NUsing F=ma, ay=mFy=5−5=−1 m/s2 Using FORMULA, v=u+atvy=uy+aytSo, 0=40−t∴t=40 SEC |
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