This problem is likely the most difficult problem of the exam. Give yourself time to consider thoughtfully, Wheels falling off moving vehicles are rare but documented and dangerous occurences.
The wheel continues to roll, reeking havoc in its path. Assume a 45 kg wheel with radius of 30 cm fell off a truck on top of a 6-m tall hill. The truck was already traveling at 20 m/s when it lost the wheel. Assume the moment of inertia of the wheel is 1 - MR. Determine the linear speed of the wheel when it reaches the bottom of the hill. m/s
Hints:
1) There are linear and rotational Ke terms both before and after rolling down the hill.
2) Use the linear equivalent of angular velocity to simplify rotational terms.
3) Don't plug in numbers until the very end of your work.

M= 700 kgvalue of g( gravity) is constant = 9.8 m/s² or 10 m/s² w = mg = 700*9.8 = 6860n or 6.680*10³ n

The figure is missing but we can answer anyway.the correct answer is "releasing the string". in fact, when the person is holding the bow and the arrow, the kinetic energy of the arrow is still zero (because the arrow is not moving). the moment the arrow is released, it acquires a velocity v, so its kinetic energy will become different from zero: where m is the mass of the arrow and v its velocity.  all the other options, instead, do not increase the kinetic energy of the system: -  pulling farther back on the string : this will just increase the elastic potential energy of the system-  holding the arrow higher: this will increase the gravitational potential energy of the system (which is given by u=mgh, where h is the height above the ground)-  decreasing the mass of the arrow: this will decrease the gravitational potential energy of the system (which is given by u=mgh, where m is the mass)