Alan

10e-2 what?  Minutes? Hours? Days? Degrees? ... etc.

Like so:

Note there is a difference between  x^2 = 4, for which x = ±2,  and  x = √4, for which x = +2 only.

√(4x^2) = 2∣x∣     and  √(x^2) = ∣x∣

so we have:   3∣x∣ = 6 + 3x

Angular velocity =angular acceleration*time (when starting from zero angular velocity), so  $\omega=0.75\times4.7\text{ rad/s}$

Linear velocity = angular velocity*radius, so $v = \omega\times21\text{ cm/s}$

You can crunch the numbers.

This might help:

Like so:

Like so:

As follows:

AS follows:

"For how many values of ? is it true that"  For how many values of what?