A 20-kg block slides down a fixed rough curved track The block has a speed of 5 0 m/s after its height above a horizontal surface has decreased by 1.8 m. Assume the block starts from rest. How much work is done on the block by the force of friction during this descent?​

Astone dropped into a well is heard to strike the water after 8seconds. find the depth of the well if the velocity of sound is 350m/s

Let v1, v2, w be three linearly independent vectors in r 3 . that is, they do not all lie on the same plane. for each of the following (infinite) set of vectors, carefully sketch it in r 3 , and determine whether or not it is a vector space (i.e., a subspace of r 3 ). explain your reasoning

Determine the maximum r-value of the polar equation r =3+3 cos 0