Question

the velocity acquired by a body moving with uniform acceleration is 20 m/ s in first 2 sec and 40 m/ s in first 5 sec. calculate intial velocity.

please questions = 7th and 8th question. ​

Answer 1

Explanation:

at t=2s,v=30m/s

at t=4s,v=60m/s

so,acceleration

a=dv/dt=(60-30)/(4-2) thus,

a=30/2=15m/s

now , v=u +at

initial velocity will be calculated using

u=v-at

after two seconds

u=30-15×2

thus, initial velocity u=0m/s.

I hope it will help u..........

Answer 2

Let$t_1$=2sec;$t_2$=5sec-2sec =3sec (as it is mentioned as first 5sec )

$u_2$=20m/s;u to be found

V=40m/s

a=$u_2-u$/$t_1$

a=$v-u_2$/$t_2$ equating these values u get u=0