Question

A body is moving with a uniform acceleration and describes 75 m in th 6th second and 115 m in 11th second . Show that it moves 155 m in 16th second .Also find acceleration and velocity ?

Answer 1

Distance travelled in the nth second,

s = u +(a/2)(2n-1)

For n =6, s = 75m

=>75 = u +(a/2)(2*6-1)

=> 75 = u + 5.5a ..................(1)

For n = 11 , s = 115m

115 = u + (a/2)(2*11-1)

115 = u + 10.5a ...................(2)

Do eqn (2) -eqn(1)

40 = 5a

=> a = 8m/s2

From (1),

75 = u + 5.5*8

=> u = 33m/s

Now for n= 16s ,s=?

s = 33+ (8/2)(2*16-1)

=> s = 157m