Answer: 7022.2kg/m³, yes, I was cheated
Explanation:
Density of an object is defined as the ratio of the mass of the object to its volume. Mathematically;
Density = Mass/Volume
Note that the unit of both mass and volume must be standard unit.
Given mass = 0.0158kg
Dimension of the metal = 5mm×15mm×30mm
Note that 1mm = 0.001m
The volume of the metal will be
0.005×0.015×0.03
= 0.00000225m³
Density = 0.0158/0.00000225
Average density of the metal = 7022.2kg/m³
Since the standard density of Gold is 19,320kg/m³ and is higher than the density prescribed for me, it shows the I was cheated.
This question deals with the law of conservation of momentum, which basically says that the total momentum in a system must stay the same, provided there are no outside forces. Since you were given the mass and velocity of the two objects you can find the momentum (p=mv) of each and then add them together to find the total momentum of the system before they collide. This total momentum must be the same after they collide. Since you have the mass and velocity of one of the objects after the collision you can find the its momentum after. Subtract this from the the system total and you will have the momentum of the other object after the collision. Now that you know the momentum of the other object you can find its velocity using p=mv and its mass from before.
Be careful with the velocities. They are vectors, so direction matters. Typically moving to the right is positive (+) and moving to the left is negative (-). It is not clear from your question which direction the objects are moving before and after the collision.
Answer:
see explanation below
Explanation:
Given that,
500°C
= 25°C
d = 0.2m
L = 10mm = 0.01m
U₀ = 2m/s
Calculate average temperature

262.5 + 273
= 535.5K
From properties of air table A-4 corresponding to
= 535.5K 
k = 43.9 × 10⁻³W/m.k
v = 47.57 × 10⁻⁶ m²/s

A)
Number for the first strips is equal to


Calculating heat transfer coefficient from the first strip


The rate of convection heat transfer from the first strip is

The rate of convection heat transfer from the fifth trip is equal to


Calculating 

The rate of convection heat transfer from the tenth strip is


Calculating

Calculating the rate of convection heat transfer from the tenth strip

The rate of convection heat transfer from 25th strip is equal to

Calculating 

Calculating 

Calculating the rate of convection heat transfer from the tenth strip

Answer:
C
Explanation:
To solve this question, we will need to develop an expression that relates the diameter 'd', at temperature T equals the original diameter d₀ (at 0 degrees) plus the change in diameter from the temperature increase ( ΔT = T):
d = d₀ + d₀αT
for the sphere, we were given
D₀ = 4.000 cm
α = 1.1 x 10⁻⁵/degrees celsius
we have D = 4 + (4x(1.1 x 10⁻⁵)T = 4 + (4.4x10⁻⁵)T EQN 1
Similarly for the Aluminium ring we have
we were given
d₀ = 3.994 cm
α = 2.4 x 10⁻⁵/degrees celsius
we have d = 3.994 + (3.994x(2.4 x 10⁻⁵)T = 3.994 + (9.58x10⁻⁵)T EQN 2
Since @ the temperature T at which the sphere fall through the ring, d=D
Eqn 1 = Eqn 2
4 + (4.4x10⁻⁵)T =3.994 + (9.58x10⁻⁵)T, collect like terms
0.006=5.18x10⁻⁵T
T=115.7K
Answer:
The force on second wheel is twice off the force on first wheel.
Explanation:
In this case, two wheels can rotate freely about fixed axles through their centers. We know that, in rotational mechanics, the torque is given by :

Also, 
And moment of inertia is, 
It implies,
Here, one has twice the radius of the other. Ratio of forces will be :

So, the force on second wheel is twice off the force on first wheel.