Question

A car starting from point P moves 100m towards the north direction in 15s , it then moves 100m towards the south direction in 20s . The velocity of the car is ___ m/s(​

Answer 1

Answer:

$Initial speed of the car is u.</p><p></p><p>Final speed of the car v=0</p><p></p><p>Let the retardation of the  car be a.</p><p></p><p>Using  v2−u2=2aS</p><p></p><p>Or  0−u2=2aS</p><p></p><p>⟹ S∝u2   (for same a)</p><p></p><p>Given :  S=40m    u′=2u</p><p></p><p>∴ SS′=u2(u′)2=22</p><p></p><p>Or  40S′=4</p><p></p><p>⟹  S′=160m</p><p></p><p>$

Answer 2

Let t be the time in seconds from the beginning of the motion of a particle. If the particle has a velocity of 4 m/s initially (at t=0) and has a constant acceleration of 2 m/s2, find the velocity of the particle:

when t=1

when t=2

after t seconds.

Draw the velocity–time graph for the motion.

Solution

When t=1, the velocity of the particle is 4+2=6 m/s.

When t=2, the velocity of the particle is 4+2×2=8 m/s.

After t seconds, the velocity of the particle is 4+2t m/s.