I would say a. hope this helps
Answer:
hellooooo :) ur ans is 33.5 m/s
At time t, the displacement is h/2:
Δy = v₀ t + ½ at²
h/2 = 0 + ½ gt²
h = gt²
At time t+1, the displacement is h.
Δy = v₀ t + ½ at²
h = 0 + ½ g (t + 1)²
h = ½ g (t + 1)²
Set equal and solve for t:
gt² = ½ g (t + 1)²
2t² = (t + 1)²
2t² = t² + 2t + 1
t² − 2t = 1
t² − 2t + 1 = 2
(t − 1)² = 2
t − 1 = ±√2
t = 1 ± √2
Since t > 0, t = 1 + √2. So t+1 = 2 + √2.
At that time, the speed is:
v = at + v₀
v = g (2 + √2) + 0
v = g (2 + √2)
If g = 9.8 m/s², v = 33.5 m/s.
Answer:
<em>The centripetal acceleration would increase by a factor of 4</em>
<em>Correct choice: B.</em>
Explanation:
<u>Circular Motion</u>
The circular motion is described when an object rotates about a fixed point called center. The distance from the object to the center is the radius. There are other magnitudes in the circular motion like the angular speed, tangent speed, and centripetal acceleration. The formulas are:


If the speed is doubled and the radius is the same, then


The centripetal acceleration would increase by a factor of 4
Correct choice: B.
Answer:
40 m/s
Explanation:
given,
height of the fall, h = 82 m
time taken to fall, t = 1.3 s
rock velocity, v = ?
acceleration due to gravity, g = 9.8 m/s²
rock is released initial velocity, u = 0 m/s
using equation of motion
v² = u² + 2 a s
v² = 0 + 2 x 9.8 x 82
v² = 1607.2
v = 40 m/s
hence, rock's velocity is equal to 40 m/s