Question

Please help me outplease show solvings​

Answer 1

Answer:

5) The approximate height is about 80 m. Choice (c)

6) The stone takes about 3 seconds to rise to its maximum height

Explanation:

Free Fall Motion

A free-falling object falls under the sole influence of gravity. Any object that is being acted upon only by the force of gravity is said to be in a state of free fall.

If an object is dropped from rest in a free-falling motion, it falls with a constant acceleration called the gravitational acceleration, which value is $g = 9.8 m/s^2$.

The distance traveled by a dropped object is:

$\displaystyle y=\frac{gt^2}{2}$

Question 5

Given the stone reaches the ground in t=4 seconds, the height of the tower is:

$\displaystyle y=\frac{9.8*4^2}{2}=78.4\ m$

The approximate height is about 80 m. Choice (c)

Question 6

Vertical Motion

The vertical motion of an object is controlled by the force of gravity. This means that there is a non-zero net force acting on the object that makes it accelerate downwards.

If the object is thrown upwards at speed vo, its speed at time t is:

$v_f=v_o-g.t$

The stone reaches its maximum height when the final speed is zero, thus:

$v_o-g.t=0$

Solving for t:

$\displaystyle t=\frac{v_o}{g}$

The stone is thrown vertically upwards with vo=30 m/s, thus:

$\displaystyle t=\frac{30}{9.8}$

$t=3.06\ s$

$t\approx 3\ s$

The stone takes about 3 seconds to rise to its maximum height