Question

a particle starts to move with initial velocity 10 m/s and under uniform retardation 2 cm/s^2. find (i) velocity of the particle after 15 seconds; (ii) distance travelled in 15 seconds; (iii) time to travel a distance of 24 cm; (iv) velocity after travelling a distance of 11 cm; (v) distance travelled in 8th second

Answer 1

(i) Velocity after 15s
v = u + at
v = 10 + (0.02 * 15)
v = 10.3 m/s

(ii) Distance travelled in 15s
S = ut + 0.5at^2
S = 10*15 + (0.5 * 0.02 * 15^2)
S = 152.5 m

(iii) Time to travel distance of 24 cm
S = ut + 0.5at^2
24 = 1000t + 0.5*2t^2
24 = 10^4t + t^2
Solve this equation to get time t

(iv) Velocity after travelling Distance 11 cm
v = sqrt(u^2 + 2aS)
v = sqrt(10^6 + 44)
v = 1 km/s

(v) Distance travelled in 8th second
S = u + a(n - 1/2)
= 10 + 0.02(8 - 1/2)
= 10.15 m

Note: I don’t think the units given in question are correct.