18) A uniform ball is released from rest on a no-slip surface, as shown in the figure. After reaching its lowest point, the ball begins to rise again, this time on a frictionless surface. When the ball reaches its maximum height on the frictionless surface, it is No slip Frictionless A) higher than when it was released. B) lower tha C) at the same height from which it was released. D) It is impossible to tell without knowing the mass of the ball. E) It is impossible to tell without knowing the radius of the ball. when it was released. Explain why.

A 34.5-kg child is on a swing attached to ropes that are L = 1.29 m long. Take the zero of the gravitational potential energy to be at the position of the child when the ropes are horizontal. a) Determine the child's gravitational potential energy when the child is at the lowest point of the circular trajectory. -436.6 J You are correct. Your receipt no. is 157-4178 ? Previous Tries b) Determine the child's gravitational potential energy when the ropes make an angle of 45.0° relative to the vertical. 312.84 J Submit Answer Incorrect. Tries 7/99 Previous Tries

5) A brick is moving on a rough level surface. It has 24 J of kinetic energy, and the friction force on it is a constant 0.50 N. What is the maximum distance it can slide? A) 24 m B) 2.0 m C) 48 m D) 12 m 6) The kinetic friction force that a horizontal surface exerts on a 60.0-kg object is 50.0 N. If the initial speed of the object is

A girl Lifes a 30 kg package 2m at constant speed. This takes 0.800 seconds A) determine her average power B) if she lifts the 30 kg package 2m with a 350 N vertical force and this takes her 0.200 seconds determine her average power C) determine the final kinetic energy of the package if it was lifted from rest