A body travels a distance of 2m in 2s. 2.8m in next 4sec.What will be speed of body in 10th second of its journey.

Answer 1

S=ut+1/2at²
2=2u+2a------>(1)
4.8=6u+18a---->(2)

Multiplying (1) by 3,
6u+6a=6
6u+18a=4.8
-------------
-12a=1.2
a=-0.1 m/s²
Therefore,
u=(2-2a)/2= 0.8 m/s

Hence, distance travelled in the 10th second is---> S=u-1/2a(2n-1)
S=0.8-0.1(20-1)= 0.8-1.9= -1.1m( displacement) which is 1.1m in distance