Question

A particle moves according to the law $x=Acos\left(\pi t\right)$. The distance covered by it in the time interval between t = 0 and t = 3.5s is:

• A. 3A
• B. 2A
• C. A
• D. 7A

Answer 1

The correct option is D 7A

A particle moves according to the equation $x=Acos\pi t$

Thus the particle is at the extreme position

Time period $T=\frac{2\pi }{\pi }=2seconds$

It means that again when it reaches the same extreme position it will do it in 2 seconds by covering 4A distance(A distance in each 0.5second)

For the next 1.5 seconds, it will cover 3A distance.

Hence, total distance the particle will cover$=4A+3A=7A$