Can a body having zero velocity move with uniform speed? give an example.

Sure. Body can move with uniform speed, and having zero velocity, when velocity becomes zero due to change in direction over time t.

For Example. - An Object is moving with uniform speed in a circular path, then after one complete revolution, it's velocity is zero, but speed still remains uniform 

Hope this helps!

Answer: fn = wcos50 = 38.89(9.81)(cos50) = 245.23 n