Could you please help me out with the following problems please?

If a rocket initially at rest accelerates at a rate of 50 m/s^2 for one minute, its speed will be ? ( I know there are 60 seconds in 1 minute, so would I just use the formula, d=vt, and I would get 3000 m/s)


It takes 6 seconds for a stone to fall to the bottom of a mine shaft. How deep is the shaft? (This one, I don't understand)

If a projectile is fired straight up at a speed of 10 m/s, the total time to return to its starting position is about (This one I don't understand)

A man leans over the edge of a cliff and throws a rock upward at 4.9 m/s. How far below the level from which it was thrown is the rock 2 seconds later? (would the formula for this one be d=vt (4.9m/s)(2s)= 9.8 m/s