Question

If the position of a particle is changing with time as r=t2-2t (m). Find the velocity at t=2s.

• A. 2 m/s
• B. 3 m/s
• C. 0 m/s
• D. 4 m/s

Answer 1

Answer: (A)

2 m/s

Answer 2

To find the velocity at a specific time, we need to take the derivative of the position function with respect to time:
$v = \frac{dr}{dt}$
In this case, the position function is given by r = t^2 - 2t (m). Taking the derivative with respect to time, we get:
$v = \frac{dr}{dt} = \frac{d}{dt} (t^2 - 2t) = 2t - 2$
To find the velocity at t = 2s, we substitute t = 2 into the expression for v:
$v = 2t - 2 = 2(2) - 2 = 2 (\frac{m}{s})$
Therefore, the velocity of the particle at t = 2s is 2 m/s, which is equivalent to option 1.
**Answer. **A