If the displacement of an object is given in SI units by Δx = −3t + 4t ²,at t = 2 s its velocity and acceleration are,respectively: A)positive,positive. B)positive,negative. C)negative,negative. D)negative,positive.

Question

Quizplus · Accepted Answer

The velocity is the first derivative of displacement with respect to time, v = d(Δx)/dt = -3 + 8t. At t = 2 s, v = -3 + 16 = 13, which is positive. The acceleration is the derivative of velocity with respect to time, a = dv/dt = 8, which is positive.

If the Displacement of an Object Is Given in SI