Question

The motion of a particle is described by the equation $u = at$. The distance travelled by the particle in the first 4 seconds

• A. $4a$
• B. $12a$
• C. $6a$
• D. $8a$

Answer 1

Answer: (D)

$8a$

Answer 2

$u = at$ ⇒ $\frac{ds}{dt} = at$

⇒ $s = \int_{0}^{4}{atdt} = a\left\lbrack \frac{t^{2}}{2} \right\rbrack_{0}^{4}$= 8a.