Question

7. a body is moving with a uniform acceleration. its velocity after 5 sec is 25m/s and after 8 sec is 34m/s. calculate the distance it will cover in 10th sec.

Answer 1

Given that
Initial velocity (U) = 25m/s
Final velocity (V) = 34m/s
Time (t) = 8-5 = 3sec
therefore Acceleration = V - U/t = 34 - 25/3 = 9/3 = 3

distance travelled in nth sec = U + A(n - 0.5)
distance travelled in 10th sec = 25 + 3(10 -0.5)
                                               = 25 + 3(9.5)
                                               = 25 + 28.5
                                               = 53.5 m

Answer 2

v = u + a t
25 = u + 5 a    
34 = u + 8 a

=>   3 a = 9  =>  a = 3 m/sec^2
u = 25 - 15 = 10 m/sec

distance covered in 10th sec:  S_10 = u + (n - 1/2 ) a
             = 10 + (10 -1/2) * 3 = 38.5 m