Please give detailed answers with necessary steps?

Question

1) Two balls A and B are thrown imultaneously, A vertically upwards with a speed of 20m/s from the ground and B vertically downwards from a height of 40 m with the same speed along the same line of motion. When &where will they meet?

2) A body let fall from the top of a tower falls through 7/16 of its height during the last second of its fall. What is the height of the tower?

3) A body moving with uniform acceleration has velocities 20m/s & 30m/s when passing points P&Q in its path. Find the velocity midway between P&Q.

4) In a 100 m race which a sprinter clears in 11s, calculate his initial uniform acceleration & its duration, if his speed remains constant at 10m/s thereafter

5) An electron moving at a speed of 5000000m/s is shot through a sheet of paper of thickness 2100000m. The electron emerges out with a speed of 2000000m/s. Find the time taken by the electron to pass through the paper.

6) A stone thrown vertically up went up 98m & came down. How long was it in air?

Answer 1

Ball A,H=-1/2x(9.8)t^2+20t

Ball B,40-H =+1/2x(9.8)t1^2+20t1,t=t1 when they meet,

40-H =40-(-4.9t^2+20t)=4.9t^2+20t,then 40+4.9t^2-20t=4.9t^2+20t so 40=40t & t=1sec.and 15.1 meter above the ground.

Answer 2

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