Become more positive instead of negative
Answer:
Second Trial satisfy principle of conservation of momentum
Explanation:
Given mass of ball A and ball B 
Let mass of ball
and
Final velocity of ball 
Final velocity of ball 
initial velocity of ball 
Initial velocity of ball 
Momentum after collision 
Momentum before collision 
Conservation of momentum in a closed system states that, moment before collision should be equal to moment after collision.
Now, 
Plugging each trial in this equation we get,
First Trial

momentum before collision
moment after collision
Second Trial

moment before collision
moment after collision
Third Trial

momentum before collision
moment after collision
Fourth Trial

momentum before collision
moment after collision
We can see only Trial- 2 shows the conservation of momentum in a closed system.
Answer:
Explanation:
Given that,
Mass of the thin hoop
M = 2kg
Radius of the hoop
R = 0.6m
Moment of inertial of a hoop is
I = MR²
I = 2 × 0.6²
I = 0.72 kgm²
Period of a physical pendulum of small amplitude is given by
T = 2π √(I / Mgd)
Where,
T is the period in seconds
I is the moment of inertia in kgm²
I = 0.72 kgm²
M is the mass of the hoop
M = 2kg
g is the acceleration due to gravity
g = 9.8m/s²
d is the distance from rotational axis to center of of gravity
Therefore, d = r = 0.6m
Then, applying the formula
T = 2π √ (I / MgR)
T = 2π √ (0.72 / (2 × 9.8× 0.6)
T = 2π √ ( 0.72 / 11.76)
T = 2π √0.06122
T = 2π × 0.2474
T = 1.5547 seconds
T ≈ 1.55 seconds to 2d•p
Then, the period of oscillation is 1.55seconds
The correct answer is A. The strands are different. Hope this helps! :)