Question

. A ball falls off a table and reaches the ground in 1 s. Assuming g = 10 m/s2 , calculate its speed on reaching the ground and the height of the table.

Answer 1

initial speed = u = 0m/s
acceleration = a = g = 10m/s²
final speed = v = ?
time = t = 1s
distance = height = s = ?

1) a = (v-u)/t
at = v-u
at+u = v
10(1)+0 = v
10m/s = v

2) v²-u² = 2as
(v²-u²)/2a = s
(100-0)/2(10) = s
100/20 = s
5m = s

it's speed on reaching the ground is 10m/s
and it falls from 5m hieght

Answer 2

Answer:

Initial velocity u=0 Let final velocity is v and height is h.

Using v=u+at

⇒v=0−10×1=−10m/s

Using s=ut+

2

1

at

2

⇒−h=0×1−

2

1

×10×1

2

⇒h=5m