Q123 / 160 · TS EAMCET 2021 (05 Aug Shift 1) · Physics

Two cars A and B initially at rest are moving in the same direction with accelerations, a1 and a2 respectively. After a certain time, they achieve velocities v1 and v2 respectively and are separated by a distance of 50 m. If a1-a2=4 m s-2, then the quantity v1-v2 will be

  • A
    24 m s-1
  • Correct answer
    B
    20 m s-1
  • C
    40 m s-1
  • D
    12 m s-1

Solution

Use the first equation of motion, v=u+at, both the cars are initially at rest it means the equations for two different cars moving with difference acceleration after same time, 
v1=0+a1t & v2=0+a2t⇒v1-v2=a1-a2t  ...1
, now the use the second equation of motion, 
s1-s2=12a1t2-12a2t2⇒t2=2s1-s2a1-a2⇒v1-v22s1-s22=2s1-s2⇒v1-v2=2s1-s2a1-a2⇒v1-v2=2×50×4=20 m s-1
 

Hence, the correct answer is option: 'B'.

Relevant Questions