Question

If you know that the rock fell 4.9 m in 1 s , how far did it drop in the first 0.5 s after you dropped it?

Answer 1

Answer

1.225 m

Explanation

The formula for getting the distance cover in this case is;

s = ut + 1/2 gt²

Where u⇒intial velocity

t⇒time taken

g ⇒ acceleration due to gravity

But in this case u = 0, t = 1 and s =4.9.

So, the first thin is to calculate the value of g.

S = 1/2 gt²

4.9 = 1/2 g × 1²

g = 4.9 × 2

= 9.8 m/s².

Now calculate the distance after 0.5 s.

S = 1/2 × 9.8 × 0.5²

= 1.225 m

Answer 2

When an object is free-falling, no other force is acting upon it but the gravitational force. Because of this, the equations of motion are simplified. We can determine first the initial velocity:

v = √2gy = √2(9.81)(4.9) = 9.805 m/s

Then, we use this to the equation below:
y = vt + 1/2*at²
y = (9.805)(0.5) + 1/2(9.81)(0.5)²
y = 6.13 m