Einstein's Big Idea homepage. E = mc2. It's the world's most famous equation, but what does it really mean? "Energy equals mass times the speed of light squared." On the most basic level, the equation says that energy and mass (matter) are interchangeable; they are different forms of the same thing.
Answer:
The law of conservation of momentum is one of the most prominent laws in physics. The principle of conservation of momentum law tells us that the total momentum of a system is always conserved.
The inertia of an object is its resistance to linear acceleration due to an applied force—that is to say, the inertia of the physicist's friend is her mass.
Apply the conservation of linear momentum for the situation wherein two colliding objects separate after the collision:
m₁v₁ + m₂v₂ = m₁v₁' + m₂v₂'
Let us choose m₁ to be the mass of the physicist. v₁ and v₁' are velocities of the physicist before and after the collision, respectively.
m₂ is the mass of the physicist's friend. v₂ and v₂' are the velocities of the friend before and after the collision, respectively.
Given values:
m₁ = 81kg
v₁ = 7.0m/s
v₁' = 4.0m/s
v₂ = 5.0m/s
v₂' = 8.0m/s
Plug in the given values and solve for m₂
81×7.0 + 5.0m₂ = 81×4.0 + 8.0m₂
3.0m₂ = 243
m₂ = 81kg
Answer:
Total time taken(T) = 1.1 hour
Distance = 75.68 km
Explanation:
Given:
Average speed = 68.8 km/h
Constant speed = 98.5 km/h
Rest time = 20 min = 20 / 60 = 0.3333 hour
Find:
Total time taken(T)
Total distance (D)
Computation:
Distance = speed × time
D = 68.8 × t.........Eq1
and
D = 98.5 × [t-0.33]
D = 98.5 t - 32.8333.........Eq2
From Eq1 and Eq2
68.8 t = 98.5 t - 32.83333
29.7 t = 32.83333
t = 1.1
Total time taken(T) = 1.1 hour
Distance = speed × time
Distance = 68.8 × 1.1
Distance = 75.68 km
<span>PV is actually energy. P = F/A force per area, and V = A L, so PV = F L and force times distance is work which is energy. If you have P in N/m^2 and V in m^3, you have Joules, N-m.</span>