If a particle starts from rest and accelerates according to

If a particle starts from rest and accelerates according to the graph shown, the particle\'s velocity at t = 20 s is A) 200 m/s B) 100 m/s C) 0 D) 20 m/s The particle in Problem 1 stops moving at t = A) 10 s B) 20 s C) 30 s D) 40 s

Solution

From the graph

a=0.5t-10

Integrating on both sides

V=0.25t^2-10t+C

At t=0, V=0

=> C=0

Hence, V =0.25t^2-10t

Particle velocity at t=20 s is

V=0.25(20)^2=100 m/s

2)

0.25t^2-10t=0

0.25t=10

t=40 s