Can u help me answer these 3 question pls in less than 30 mins pls i solved both of them but im not sure if im correct thanks Assuming the track is frictionless, how much higher than the top of the loop does the marble have to start in order to make sure it achieves critical velocity?(: Use critical velocity in your kinetic energy equation, and consider that only the height above the top of the roller coaster is converted into kinetic energy.)a.The marble must start above the top of the loop by a distance equal to the radius of the loop.b.The marble must start above the top of the loop by a distance equal to the 1/2 the radius of the loop.C.The marble must start above the top of the loop by a distance equal to the twice radius of the loop.d.The starting height of the marble is not related to the radius of the loop.If the coaster is travelling through point 2 (at some speed higher than critical velocity) which of the following forces are needed to keep coaster the circular path? Select all that apply.a.)force of inertiab.)gravitational forceC.)normal force from the trackD.)force of tension4.if we know the conservation of energy, which of the following statements is true if we assume the track is NOT frictionless?a.The total mechanical energy of the coaster increases as it rolls down the track.b.The total mechanical energy of the coaster is the same at any point on the track.C. The total mechanical energy of the coaster decreases as it rolls down the track, while its thermal energy (internal energy) increases.