A dachshund with a mass of 4.8kg is sitting on a 1.5kg sled moving at 2.0 m/s. if the dog jumps off the sled, with what velocity will the sled continue moving?

Suppose that 27 j of work is needed to stretch a spring from its natural length of 6 m to a length of 9 m. (a) how much work is needed to stretch the spring from 12 m to 14 m? j (b) how far beyond its natural length will a force of 78 n keep the spring stretched?