Hello All, Would really appreciate your help, with the following questions : With positive value of acceleration, acceleration must be speeding up. If so why? ... I really didn't understand this question. A ball is dropped from a height of 90 m on a floor. At each collision with the floor, the ball loses one tenth of its speed. Plot the speed-time graph of its motion between t=0 to 12 seconds For, this u= 0, s= -90, t = 12 seconds. So I use v2 = u2 + 2as? After doing that I get V. But how do I calculate the number of collisions? The speed time graph f a particle moving along a fixed direction is shown in the picture. Obtain the distance traversed by the article between ... (a) t = 0 s to 10 s and ... (b) 2 s to 6s For the first instance its just 1/2 * b * h = 0.5 * 10 * 12 = 60 m But for the second one, I don't know the value of speed (height). Therefore, how can I calculate area of the triangle for the distance? Thanks in advance!