Answer:
Explanation:
PE = mgh where m is the mass, g is gravity, and h is the height from which the object can potentially fall. We are given enough info here to solve for h. Filling in:
42 = 1.8(9.8)h and
and rounding to 2 sig fig's as we need:
h = 2.4 m, choice D
I just googled refraction vs reflection. Hope this helps! :)
Answer:
t = o.6 s
Explanation:
Let ball thrown from below be A and ball dropped from above be B.
A and B meet when they both are same level above the ground. Then let A moved up a distance d and B dropped a distance h. Then you know
d + h = 15 m ---------------(1)
Now apply s = ut + 
at²
To A upwards,
d = 25t - gt² -----------------(2)
To B downwards,
h = 0 + gt² ----------------(3)
(1) = (2) + (3) ⇒ 15 = 25t
t = 0.6 s
At the initial state: v1 = vf = 0.001053 m
3
/kg, h1 = hf = 467.11 kJ/kg, and s1 = sf = 1.4336 kJ/kgK.
The mass of the water is: m = V/v1 = 0.005/0.001053 = 4.7483 kg.
To find the final state, we will use the First Law:
Q12 = m(h2 - h1) for closed system undergoing a constant pressure process.
h2 = 1Q2/m + h1 = 2200/4.7483 + 467.11 = 930.43 kJ/kg.
At P2 = P1 = 150 kPa, this is a saturated mixture.
hf = 467.11 kJ/kg, hfg = 2226.5 kJ/kg, sf = 1.4336 kJ/kgK, and sfg = 5.7897 kJ/kgK
s2 = sf + sfg (h2 – hf )/hfg = 1.4336 + 5.7897(930.43 – 467.11)/2226.5 = 2.6384 kJ/kgK.
The entropy change of water is:
Delta Ssys= m(s2 – s1) = 4.7483(2.6384 – 1.4336) = 5.72 kJ/K.
Average acceleration = (change in speed) / (time for the change) .
Change in speed = (ending speed) - (beginning speed)
= (9.89 miles/hour) - (2.35 yards/second) = 26,839.2 ft/hr
Acceleration = (26,839.2 ft/hr) / (4.67 days) = 2,873.58 inch/hour²
