Let V = the volume of the balloon
Force of gravity = V * ?hot * g downward
Buoyant force = V * ?cool * g upward
Net upward force F = V * ?cool * g - V * ?hot * g
F = V g (?cool - ?hot)
Mass of the balloon m = V ?hot
a = F/m = V g (?cool - ?hot)/(V ?hot)
a = g(?cool/?hot - 1)
a = 9.8(1.29/0.93 - 1)
a = 3.79 m/s^2
<span>Answer is 3.79 m/s^2</span>
Answer:
D, rubber
Explanation:
Metals have free electrons, and are very bad as insultators. Metals conduct electricity very well. On the other hand, rubber has no free electrons and does not conduct electricity very well
Boat speed is 68km/h both to and fro.
boat b speed to is 34km/h and back is 102km/h
time taken by boat to is distance/speed= 68 km/68km/h=1 hour
and fro is 68km/68km/h=1 hour
for the whole trip boat a took 2 hours
boat b speed to is 34km/h and distance is 68km, so it took 68km/34km/h = 2 hours to and fro it took 68km/102km/h=0.67 hours
for the whole trip boat b took 2.67 hours
so boat a is the winner as it took 2 hours to complete the challenge.
C. Figure 11 and figure 1v are both compounds
Answer: option D. 4
Reasoning:
Assuming that the time elapsed between any two consecutive dots is the same, and that the second dot marks second 1, the column with 3 dots marks second 2, and the dot right most marks second 3, the motorcycle has positive acceleration after 4 seconds.
That is because:
1) from the first dot to the second dot: the velocity the lenght of the arrow that models the velocity decrases, which means that the acceleration is negative.
2) In the nex group of dots the length of the arrow remains equal, which means that the velocity is constant and the acceleration is 0.
3) For the last dot, the length of the arrow is greater, which means that the velocity increases, and so the acceleration is positive.
