<span>Kinematics is used in this problem. The mass does not matter here because the question is mass independent.
vi = 0
vf = x
d = ?
d = vi + 1/2 a t^2
d = 0 + 1/2 (9.8) (1.8)^2
d = 15.9 m (counting sig figs)</span>
Answer: D
Reduced impact time will increase the impact force
Explanation: Collision occurs when two or more bodies collide and exert forces on each other within a short time.
If a body of mass M moving with a velocity V collide with another body, the kinetic energy of the body is equal to the work done by the body.
That is, K.E = 1/2mv^2 = F × s
Where workdone = Force × distance
Make F the subject of formula
Mv^2/2s = F
But V = distance s/time t
Substitute for V
Ms^2/2t^2s = F
Ms/2t^2 = F
From the equation above, we can deduce that F is inversely proportional to the square of time.
Therefore, the reduced impact time will increase the impact force
D, I believe is the correct answer. Hope I answered your question, have a good day.<span />
