A person ties a 2.5 g ball to the end of a 200 cm rope and swings it around in a circle directly over their head. It takes the ball 1.2 seconds to move around the circle one time. What type of force provides the centripetal force?

Will you chech and finish these for me, because i am stumped with them.

The rigid beam is supported by the three suspender bars. bars ab and ef are made of aluminum and bar cd is made of steel. if each bar has a cross-sectional area of 450 mm2, determine the maximum value of p if the allowable stress is (σallow)st = 200 mpa for the steel and ( σallow)al = 150 mpa for the aluminum. est = 200 gpa and eal = 70 gpa.

Give one example to show that when substances are mixed,it may result in a chemical or a physical change depending on the conditions.