What is the centripetal acceleration of a point on the edge

Question

1. A drive pulley 8 cm in diameter is set to rotate at 9 rev/s. What is the centripetal acceleration of a point on the edge of the pulley (m/s²)? What would be the linear speed of a belt around the pulley(m/s)?
2. A simple pendulum 1 m long has an 8 kg bob. How much work is needed to move the pendulum from its lowest point to a horizontal position?
3. A 15 lb hammer moving at 75 ft/s strikes the head of a nail moving it into a wall a distance of 1/6 in. What was the average stopping force?
4. A worker lifts a 50 lb weight through a height of 10 ft. How many meters can a 14 kg block be lifted by the same amount of work?
5. A horizontal force pushes a 24 kg sled along a driveway for a distance of 30 m. If the coefficient of sliding friction is 0.2, what is the work done by the friction force?
6. A sled is dragged a distance of 12.2 m by a rope under constant tension of 134 N. The task requires 1250 J of work. What angle does the rope make with the ground?
7. A 40 kg sled is pulled horizontally for 470 m (µ_k = 0.2). If the resultant work is 55 kJ, what was the parallel pulling force?