Flat throw sports photography

(1) The ball makes a flat throwing motion, and the flat throwing motion makes a uniform linear motion in the horizontal direction. Camera A shoots horizontal motion, so it should be equally spaced points. Therefore, the stroboscopic photo taken by camera A is B. 。

(2) Camera A shoots the uniform linear motion of the ball in the horizontal direction, and camera B shoots the free falling motion of the ball in the vertical direction. According to the a)OP distance measured in fig. B (A), h=45cm,

Then h = 12gt2,

Solution: t = 2hg = 2× 0.45 10 = 0.3s = 0.3s.

If the OP distance in (b) is s=30cm, then s=v0t,

It is found that the initial velocity of the flat projectile is v0 = st = 0.30.3 =1m/s. 。

The vertical velocity of point p is vy=gt= 10×0.3m/s=3m/s,

Therefore, the Pythagorean theorem is used to obtain the velocity of point P as v = v02+Vy2 = 33+12 =10m/s. 。

So the answer is: (1) b; (2) 1; 10.