Physics for IGCSE & O level - Forces And Motion (Section 12 - No. 33)
If the ball is thrown up with an initial velocity of +30 m/s and is falling down, what is the ball's velocity in the downward direction after 1 second?
-10 m/s
+20 m/s
-20 m/s
+10 m/s
ব্যাখ্যা
At 1 second from starting the ball, the ball will have a velocity of +30 m/s - 10 m/s = +20 m/s. The ball is at its highest point, at 3 seconds from starting the ball, it begins to fall in the downward direction. At the end of the fourth second it will have a velocity of -10 m/s