Answer:
Weight=686.7N,
, S.G.=0.933, F=17.5N
Explanation:
So, the first value the problem is asking us for is the weight of methanol. (This is supposing there is a mass of methanol of 70kg inside the tank). We can find this by using the formula:
W=mg
so we can substitute the data the problem provided us with to get:

which yields:
W=686.7N
Next, we need to find the density of methanol, which can be found by using the following formula:

we know the volume of methanol is 75L, so we can convert that to
like this:

so we can now use the density formula to find our the methanol's density, so we get:



Next, we can us these values to find the specific gravity of methanol by using the formula:

when substituting the known values we get:

so:
S.G.=0.933
We can now find the force it takes to accelerate this tank linearly at 
F=ma

F=17.5N
Answer:
Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, dust, pollen and mold spores may be suspended as particles. Ozone, a gas, is a major part of air pollution in cities. When ozone forms air pollution, it's also called smog.
Answer:
x = 4.4719 m
Explanation:
For answer this we will use the law of the conservation of energy, where:

First, we will call:
: the car in rest
: when the spring is compressed
so:


where M is the mass of the car, g the gravity, h the altitude, K is the constant of the spring and X is the spring compressed in stopping the ore car. So, replacing values, we get:

solving for x:
x = 4.4719 m
5. between the stone and the ground
for a stone at rest on the ground, we have two forces acting on the stone. first is the force on the stone by the earth due to gravity of earth. second is the force applied by the ground in upward direction to balance the force of gravity on the stone.
so first interaction is between earth and stone : earth pulls stone towards it and stone pulls earth towards it by same amount of force.
second interaction is between stone and ground : ground push the stone in upward direction and stone push the ground in down direction by same amount of force.
hence the correct choice is
5. between the stone and the ground