A body of mass 2kg travels according to the law x(t)= pt+qt2+rt3 where p=3m/s ,q =4m/s and r= 5m/s . The force acting on the body at t = 2 seconds is
(a) 136 N
(b) 134 N
(c) 158 N
(d) 68 N
A body of mass 2kg travels according to the law x(t)= pt+qt2+rt3 where p=3m/s ,q =4m/s and r= 5m/s . The force acting on the body at t = 2 seconds is
(a) 136 N
(b) 134 N
(c) 158 N
(d) 68 N
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1 Answer
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This is a Multiple Choice Questions type Questions as classified in NCERT Exemplar
Answer- a
Explanation- x (t)= pt+qt2+rt3
V= dx/dt=p+2qt+3rt2
So a= o+2q+6rt
At t=2s a= 2q+6 2 (r)
= 2q+12r
= 2 (4)+12 (5)=68m/s
So F =ma= 2 (68)= 136N
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