Answer:
0.6 seconds
Explanation:
The time to fall from height h is ...
t = √(2h/g)
t = √(2(1.86 m)/(9.8 m/s^2)) ≈ √0.3796 s ≈ 0.616 s
It would take about 0.6 seconds for the projectile to hit the ground.
For a simple harmonic motion, the position of the mass at any time t is given by

where
A is the amplitude of the motion (in this problem, A=17.5 cm)

is the angular frequency of the oscillator
t is the time
The angular frequency of the motion in the problem is given by

And so, we can find the position x of the mass (with respect to the equilibrium position) at time t=2.50 s:
The answer would be C. It will decrease with descent. Hope this helps!
Explanation:
Below is an attachment containing the solution.
Answer:
B) Friction
Explanation:
The main source of error is the omission of the effect from friction between block and incline, which is directly proportional to the mass of the block. The force of gravity is constant. The friction force dissipates part of the gravitational potential energy, generating a final speed less than calculated under the consideration of a conservative system. Air resistance is neglected at low speeds like this case.