What is the boundary between the crust and the mantle called

Ashot putter releases the shot some distance above the level ground with a velocity of 12.0 m/s, 51.0 ∘above the horizontal. the shot hits the ground 2.08 s later. you can ignore air resistance. how far did she throw the shot?

Aparticle initially located at the origin has an acceleration of = 2.00ĵ m/s2 and an initial velocity of i = 8.00î m/s. find (a) the vector position of the particle at any time t (where t is measured in seconds), (b) the velocity of the particle at any time t, (c) the position of the particle at t = 7.00 s, and (d) the speed of the particle at t = 7.00

The stopwatch used by a student to measure velocity of a pulse in a slinky was of least count 0.1 second. he stops the stopwatch when a pulse has made 3 journeys from one end to the other of the slinky. he finds the seconds hand to be at 52nd division. calculate the correct time noted by him.