Answer
given,
given,
small cube side = 10 cm
larger cube side = 12 cm
density of steel = 7 g/cm³
density of aluminium = 2.7 g/cm³
density of the water (ρ₁)= 1 g/cm³
Cube A and B made of steel
buoyant force of Cube A
B₁ = ρ₁ V g = 1 x 10 x 10 x 10 x g= 1000 g
for cube B
B₂ = ρ₁ V g = 1 x 12 x 12 x 12 x g= 1728 g
buoyant force of Cube C
B₃ = ρ₁ V g = 1 x 10 x 10 x 10 x g= 1000 g
for cube D
B₄ = ρ₁ V g = 1 x 12 x 12 x 12 x g= 1728 g
buoyant force acting on the cube depends on the density of the fluid
hence,
B₂ = B₄ > B₁ = B₃
Complete Question:
Andy and Charlie are riding on a merry-go-round. Andy rides on a horse at the outer rim of the circular platform, twice as far from the center of the circular platform as Charlie, who rides on an inner horse. When the merry-go-round is rotating at a constant angular speed, which of the following best describes Andy's angular speed?'
( ) twice Charlie’s
( ) impossible to determine.
( ) the same as Charlie’s
( ) half of Charlie’s
Answer:
The same as Charlie's
Explanation:
As a merry-go-round is a rigid body, all points in the rotating body must have the same angular velocity, i.e., thet must rotate the same angle in the same time.
Otherwise, the distance between any pair of points on a given radius could be different in different times, which is not possible in a rigid body,
Answer:
3.78075x10^6 kg x meter^2/ second^2
Explanation:
Kinetic energy K= 1/2 x mass x velocity^2
Answer: 3.7×10¹²watts
Explanation:
Radiation is one of the mode of heat transfer and modes differs from each other based on their medium of heat transfer. Radiation is a process of transferring heat energy from one point to another without heating the intervening medium (no material medium is required).
According to Stefan's law of radiation, the rate of emission of radiant energy is directly proportional to the fourth power of its absolute temperature.
Mathematically, R = eAT⁴
e is constant of proportionality called emissivity. Emissivity varies depending on the type of body being considered.
For the question, we are considering black body and emissivity of black body is 1 being a perfect body.
A is the area of the body
T is the absolute temperature
e = 1
A = 0.5cm²
T = 1650°C
Rate of radiation = 1×0.5×1650⁴
= 3.7×10¹²watts.
The hole will therefore radiate 3.7×10¹²watts
Power = (work done) / (time to do the work)
= (21,000 Joules) / (30 seconds)
= (21,000 / 30) joule/sec
= 700 watts
