Answer:
The average speed for the whole journey is 49.5 miles per hour.
Explanation:
Step 1 :
Here, both the ways, he covers the same distance. Then, the formula to find average speed is
= 2xy / (x+y)
Step 2 :
x ----> Rate at which he travels from New York to Washington
x = 45
y ----> Rate at which he travels from New York to Washington
y = 55
Step 3 :
So, the average speed is
= (2 ⋅ 45 ⋅ 55) / (45 + 55)
= 4950 / 100
= 49.5
Answer:
Explanation:
Given
inclination 
initial speed 
Point of release is 45 m above the ground
Considering stone to be a projectile, so time taken by projectile for its zero vertical displacement is
Now after completing zero vertical displacement , stone needs to travel another 45 m in downward direction with initial speed u=20\sin 30
where, 
thus total time time required is 
vertical velocity just before hitting
Horizontal velocity 
Net velocity Just before hitting 
Agility is the answer. Hope this helps have an awesome day!
Answer:
No, it is not necessary for them to have same mass.
Explanation:
Let both bodies have a density d1 and d2 respectively.
Since their volumes are equal V1 = V2
we know that,
density = 
Hence, d1 = 
and d2 = 
Taking the ratio of densities,we get
This implies that unless the bodies have same densities, the mass of the two bodies will not be same.
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
