Hi, I am having problems with the following two problems: 1. The problem statement, all variables and given/known data A 1.84kg ball is swung vertically from a 0.80m cord in uniform circular motion at a speed of 2.8m/s. What is the tension in the cord at the bottom of the ball's motion? 2. Relevant equations I have tried using the centripital acceleration formula to find a, and then plugged it into the tension formula of T=ma (is that even right?), but cannot get the correct answer. 3. The attempt at a solution w²r = (1.84*pi)² * 0.8 = 2.67 m/s² Tension = ma = 2*2.67 = 5.34 N The second problem is: 1. The problem statement, all variables and given/known data The radius of the Earth is 6.38E6 m and its mass is 5.98E24 kg. What is the acceleration due to gravity at a height of 27391854.50m above the Earth's surface? (We are given that G = 6.67e-11 N*(m^2/kg^2)) 2. Relevant equations I have tried using G = 6.67e-11 N*(m^2/kg^2) to find the acceleration, as well as g= -GM/r^2, but cannot come up with anything. 3. The attempt at a solution I have used g= -GM/r^2, and plugged in 5980000000000000000000000 for M and 6380000 for r, but nothing is coming out correct. Thanks in advance!