I have tried this question but I cannot get answer!

Figure shows a 3 kg block being pulled along a frictionless floor by a cord that applies a force of constant magnitude 15 N but with an angle θ(t) that varies with time. When angle θ = 25°, at what rate is the block's acceleration changing if (a)θ(t) = (4 × 10-2 deg/s)t and (b)θ(t) = (-4 × 10-2 deg/s)t ? (Hint: Switch to radians.)

The figure is a box being pulled by force f which is θ above the x axis. ex /._

What would be the steps to solving this problem?