A projectile is fired from level ground with speed v at an angle θ to the ground. Ignoring air resistance, which of the following is a correct expression for the maximum height reached by the projectile?

A. \(\frac{{{v^2}{{\sin }^2}\theta }}{{2g}}\)

B. \(\frac{{{v^2}{{\cos }^2}\theta }}{{2g}}\)

C. \(\frac{{v\sin \theta }}{g}\)

D. \(\frac{{v\cos \theta }}{g}\)

A

This is a perfect example of a question that can be ‘seen’ without any calculation. If θ is zero the height will be zero – so it is either A or C. From consideration of the units, C gives a time (in seconds) so must be discounted.