I believe the answer is true.
Answer:
V = 381.70 m³
Explanation:
ρ air = 1.28 kg / m³
ρ helium = 0.18 kg / m³
R = 4.5 m
Vb = 0.068 m³
mb = 123 kg
To determine the volume of helium in the balloon when fully inflated
V = 4 / 3 π * R ³
V = 4 * π / 3 ( 4.5 m )³
V = 381.70 m³
To determine the mass total
m = ρ helium * V
m = 0.18 kg / m³ * 381.70 m³
m = 68.70 kg
mt = ( 68.70 + 123 )kg
mt = 191.70 kg
Over time, the types of technology can vary and be improved upon so that more advanced techniques become more valued. This could be the situation with mining whereby back in the 1500's in underground mines the rock was broken by fire setting ie lighting a fire below the rock face to heat up the rock and then throwing cold water on it to crack it, so that it could be dug by hand. With the advent of explosives, this all changed so that the rock could be blasted. The increase in advance rates for an underground heading have thus gone from 5-20 feet per month to up to 300meters (984 ft) per month for a 24/7 mining operation, which is a huge improvement.
Answer:
A) Force
Explanation:
It is an example of force since force is a vector quantity so it has magnitude and direction. In this case the magnitude is equal to 5 [N] and the direction is upward.
The weight can not be, as it always acts downward.
Mass is not a force, its unit is given usually in kilogram [kg]
Answer:
17.64 km/h
Explanation:
mass of car, m = 1000 kg
Kinetic energy of car, K = 1.2 x 10^4 J
Let the speed of car is v.
Use the formula for kinetic energy.
By substituting the values
v = 4.9 m/s
Now convert metre per second into km / h
We know that
1 km = 1000 m
1 h = 3600 second
So, 
v = 17.64 km/h
Thus, the reading of speedometer is 17.64 km/h.
