Question

A particle is moving in a straight line with initial velocity 10 metre per second and constant retardation of 4 metre per second square calculate the distance travelled by it in third second​

Answer 1

initial velocity=u=10m/s

Acceleration = -Retardation= -2 m/s2

Velocity after 4 seconds sice we have to find the distance travelled in 5th second= V5=u+at

=>V5= 10-2x4 =8m/s

Distance moved by the particle in the fifth second = Displacement of the particle in the fifth second (since they are moving in straight line)

=>Displacement=ut+at2/2

=2x1-2x1/2

=1m

Distance moved=1m.

Answer 2

1. Answer:  Explanation:    a = -4m/s² (cox whenever retardation is mentioned acceleration will be -ve) u = 10m/s  Distance travelled in nth second is given by                           Sn = u + 1/2a(2n-1)                                             = 10 + 1/2.(-4).(2×3-1)                                            = 10 - 10                                             = 0m    Hope it helped