To answer this problem, we will use the equations of motions.
Part (a): For the ball to start falling back to the ground, it has to reach its highest position where its final velocity will be zero. The equation that we will use here is: v = u + at where v is the final velocity = 0 m/sec u is the initial velocity = 160 m/sec a is acceleration due to gravity = -9.8 m/sec^2 (the negative sign is because the ball is moving upwards, thus, its moving against gravity) t is the time that we want to find. Substitute in the equation to get the time as follows: v = u + at 0 = 160 - 9.8t 9.8t = 160 t = 160/9.8 = 16.3265 sec Therefore, the ball would take 16.3265 seconds before it starts falling back to the ground
Part (b): First, we will get the total distance traveled by the ball as follows: s = 0.5 (u+v)*t s = 0.5(160+0)*16.3265 s = 1306.12 meters The equation that we will use to solve this part is: v^2 = u^2 + 2as where v is the final velocity we want to calculate u is the initial velocity of falling = 0 m/sec (ball starting falling when it reached the highest position, So, the final velocity in part a became the initial velocity here) a is acceleration due to gravity = 9.8 m/sec^2 (positive as ball is moving downwards) s is the distance covered = 1306.12 meters Substitute in the above equation to get the final velocity as follows: v^2 = u^2 + 2as v^2 = (0)^2 + 2(9.8)(1306.12) v^2 = 25599.952 m^2/sec^2 v = 159.99985 m/sec Therefore, the velocity of the ball would be 159.99985 m/sec when it hits the ground.
Almost all rocks made of minerals, but different rocks contain different mixtures of minerals. Granite<span>, for example, consists of quartz, </span>feldspar<span>, and mica.
