Potential energy is energy due to an object's height above the ground.
Potential energy = mass x gravity x height
Kinetic energy is energy due to the motion of the object.
Kinetic energy = 1/2 x mass x velocity²
1.
The ball is not moving and is at a height above the ground so it has only potential energy.
P.E = 2 x 9.81 x 40
P.E = 784.8 J
2.
The ball is moving and has a height above the Earth's surface so it has both kinetic and potential energy.
P.E = same as part 1 = 784.8 J
K.E = 1/2 x 2 x 5²
K.E = 25 J
3.
The ball has no height above the Earth's surface and is moving so it has only kinetic energy.
K.E = 1/2 x 2 x 10²
K.E = 100 J
4.
50000 = 1/2 x 1000 x v²
v = 10 m/s
5.
39200 = 200 x 9.81 x h
h = 20.0 m
6.
12.5 = 1/2 x 1 x v²
v = 5 m/s
98 = 1 x 9.81 x h
h = 10.0 m
Answer:
Mass = 279.23 g
Explanation:
Given data:
Number of moles of Fe₂O₃ = 3 mol
Number of moles of Al = 5 mol
Maximum amount of iron produced by reaction = ?
Solution:
Chemical equation:
Fe₂O₃ + 2Al → Al₂O₃ + 2Fe
Now we will compare the moles of iron with Al and iron oxide.
Fe₂O₃ : Fe
1 : 2
3 : 2×3 = 6 mol
Al : Fe
2 : 2
5 : 5 mol
The number of moles of iron produced by Al are less so Al is limiting reacting and it will limit the amount of iron so maximum number of iron produced are 5 moles.
Mass of iron:
Mass = number of moles × molar mass
Mass = 5 mol × 55.845 g/mol
Mass = 279.23 g
<span>The constant bombardment of gas molecules against the inside walls of a container produces Pressure.
Explanation:
Pressure is defined as Force per unit Area.
P = F / A
In case of gases, the gas molecules have high Kinetic Energy and they move with high velocity. This cause them to strike against the inside wall of the container. Pressure is directly proportional to temperature. Increase in temperature cause to increase the Kinetic Energy of molecules, Hence, the rate of collisions increases resulting in increasing the pressure.</span>
