Answer:
c) 8.3 x 10^24 molecules
Explanation:
First of all, we convert the volume of the glass of water from mL to :
The relationship between mass and volume is:
where
is the density of water
M is the total mass of the glass of water
is the volume of the water in the glass
Solving for M,
Now we know that the mass of a single molecule of water is
The total mass of the water in the glass can be written as
where
N is the number of molecules in the glass of water
Solving for N, we find:
Answer:
Explanation:
The equation for this, since we are talking about weight on an elevator, is Newton's 2nd Law adjusted to fit our needs:
where the Normal Force needed to lift that elevator car is the tension. So the equation then becomes
T = ma + w where T is the tension in the cable to lift the elevator, m is the mass of the elevator (which we have to solve for), a is the acceleration of the elevator (positive since it's going up), and w is the weight of the elevator (which we have as 5500 N). Solving first for mass:
w = mg and
5500 =- m(10) so
m = 550 kg. Now we have what we need to solve for the tension:
T = 550(4.0) + 5500 and
T = 2200 + 5500 so
T = 7700 N