At what height h above the ground does the projectile have a speed of 0.5v?

Express your answer in terms of v and the magnitude of the acceleration of gravity g.

Verified Answer :

Answer:

\(h=\dfrac{3v^2}{8g}\)

Explanation:

It is given that,

Speed of the projectile is 0.5 v. Let h is the height above the ground. Using the first equation of motion to find it.

\(v=u+at\)

\(v=u-gt\)

Initial speed of the projectile is v and final speed is 0.5 v.

\(0.5v=v-gt\)

\(t=\dfrac{v}{2g}\)

g is the acceleration due to gravity

Let h is the height above the ground. Using the second equation of motion as :

\(h=vt-\dfrac{1}{2}gt^2\)

\(h=v\dfrac{v}{2g}-\dfrac{1}{2}g(\dfrac{v}{2g})^2\)

\(h=\dfrac{3v^2}{8g}\)

So, the height of the projectile above the ground is \(\dfrac{3v^2}{8g}\). Hence, this is the required solution.