Question

A particle start from rest, accelerates at 2m/s² for 10s and then goes for constant speed for 30s and decelaratd s at 4m/s² till it stops after next .what is the distance c travelled by it?

Answer 1

divide the question into 3 parts and then answer it.......

1st part= v=u+at

v= 0+(2*10)

v= 20m/s = dist= s=(o*10 )+ (1/2*2*100)

= 100mtrs (eq.1)

2nd part

v=20m/s

s= v*t = 20*30= 600mtrs..... eq.2

3rd part( the accelaration given as 4m/s^2 should actually be -4m/s^2)

here v=0 = 0=u+at

0=20+(-4*t)

= t=5secs

= s=20*5 + 1/2*(-4)25

s= 100 + (-50)

s= 50mtrs.... eq3

now simply add the three distances

=100 + 600 + 50

= 750mtrs...... ans

hope it helps!!!