Question

what will the solution of this question​

Answer 1

$\huge\boxed{\mathtt\red{Solution}}$

Given :-

• Height from which the ball is dropped (displacement (s)) = 20m
• Acceleration of the ball (a) = 10 m/s²

To Find :-

• Velocity at which it strikes the ground ( final velocity (v)).
• Time in which it strikes the ground (t).

Solving :-

Here,

◑ The initial velocity (u) = 0

because, the ball is dropped from a certain height.

By applying second formula of motion :-

$\large\boxed{\mathtt\red{s=ut+\frac{1}{2}gt²}}$

where,

• s = displacement

• u = initial velocity

• t = time

• g = acceleration due to gravity (given 10 m/s²)

Putting all the values :-

✒ 20 m = (0×t) + $\large\mathtt{\frac{1}{2}×10\:m/s²×t²}$

✒ 20 m = $\large\mathtt{\frac{1}{2}×10\:m/s²×t²}$

✒ $\large\mathtt{t² =\frac {20\:m×2}{10\:m/s²}}$

✒ t² = 4 s²

✒ t = √4s²

$\large\boxed{\mathtt\green{∴ time (t) = 2 s}}$

___________________________________

Now, we need final velocity (v) :-

Applying third formula of motion :-

◑ v²-u² = 2gs

where,

• v = final velocity

• u = initial velocity

• g = acceleration due to gravity

• s = displacement

Now, putting the values :-

✒ v²- (0)² = 2×10 m/s²× 20 m

✒ v² = 400 m²/s²

✒ v² = √400 m²/s²

$\large\boxed{\mathtt\green{∴ Final\: velocity\:(v) = 200\:m/s}}$