11 A particle moving with constant acceleration along a straight line covers distance between 2 points 80 m apart - Physics - Physical World

Question

11 A particle moving with constant acceleration along a straight
line covers distance between 2 points 80 m apart in 10 seconds Its
velocity as it passed the second point is 18 m/s
(A) Its velocity at the first point is -2 m/s
(B) Its acceleration is 2 m/s2
(C) The total distance travelled during these 10 seconds is 82
m
(D) All above are false

Decoder_2 · Accepted Answer

Dear student,A) v2=u2+2aS18×18=u2+2a×80324=u2+160au=324-160av=u+at18=u+10au=18-10afrom above two equations we have324-160a=(18-10a)2324-160a=324+100a2-360a100a2-200a=0100a(a-2)=0⇒a=2 or 0so option B is correctV=u+at18=u+2×10u=-2m/soption A is correctsince velocity is negative so it will cover in total 82m in 10sRegards