Two roller coasters are being tested. Roller coaster $1$ releases its car from rest at the top of the first hill of height, $h.$ There is negligible friction with roller coaster $1$ and the car arrives at the bottom of the hill with speed v$.$ In a second trial a different car, one that has significant friction with the track, is released from the same hill, also from rest. In the second trial one$-$half of the initial mechanical energy of the carEarth system is lost due to friction as the block descends the hill. At the bottom of the hill it will have a speed of

$\frac{1}{2}v$

$$

$\frac{1}{\sqrt[\phantom{2}]{2}}v$

$$

$\sqrt[\phantom{2}]{2}v$

$$

$\frac{1}{4}v$

$$

$2v$