Question

Please help will mark Brainliest. An object is dropped from the roof of a building. After 3.5 seconds, the object strikes the ground. A.) After 2 seconds, what is the speed of the object? B.) At what speed does the object strike the ground? C.) Find the height from which the object was dropped. Show Work

Answer 1

Answer:

19.62 m/s

34.335 m/s

1.75 m

Explanation:

v = Final velocity

u = Initial velocity = 0

a = g = Acceleration due to gravity = $9.81\ \text{m/s}^2$

t = Time taken = 2 s

From the equations of linear motion we have

$v=u+at\\\Rightarrow v=0+9.81\times 2\\\Rightarrow v=19.62\ \text{m/s}$

The speed of the object after 2 seconds is 19.62 m/s

t = 3.5 s

$v=u+at\\\Rightarrow v=0+9.81\times 3.5\\\Rightarrow v=34.335\ \text{m/s}$

The velocity of the object when it strikes the ground is 34.335 m/s.

$v^2-u^2=2as\\\Rightarrow s=\dfrac{v^2-u^2}{2a}\\\Rightarrow s=\dfrac{34.335-0}{2\times 9.81}\\\Rightarrow s=1.75\ \text{m}$

THe height from which the object was dropped is 1.75 m.