posted by Courtney on .
A bullet (m = 0.0250 kg) is fired with a speed of 91.00 m/s and hits a block (M = 2.30 kg) supported by two light strings as shown, stopping quickly. Find the height to which the block rises.
Find the angle (in degrees) through which the block rises, if the strings are 0.260 m in length.
You do not describe the figure. Why are two strings needed to hold the block?
In general, use conservation of momentum to calculate the momentum of and velocity V' the block after impact, but before it starts to swing upwards. Calculate also its initial kinetic energy at that time, with the bullet inside. If the buolet velcoity is V,
m V = (M+m) V'
The initial kinetic energy
(1/2)(M+m)V'^2 is equal to the potential enewrgy increase (M+m)gH after is swings upwards a distance H. Use trigonometry to get the angle.