Answer:
• 36.4 kg of coal.
• 80 pounds of coal.
Explanation:
Using proportionality constant,
Mass of coal = 1,000,000/27,500,000 btus/metric ton
= 0.0364 metric tons of coal
Mass of coal = 1,000,000/25,000,000 btus/ton
= 0.04 tons of coal.
Converting metric tons to kilogram,
1 metric ton = 1000kg,
0.0364 metric ton;
= 36.4 kg of coal.
Converting tons to pounds,
1 ton = 2000 pounds,
0.04 metric ton;
= 80 pounds of coal.
Answer:
vB = 15.4 m/s
Explanation:
Principle of conservation of energy:
Because there is no friction the mechanical energy is conserve
ΔE = 0
ΔE : mechanical energy change (J)
K : Kinetic energy (J)
U: Potential energy (J)
K = (1/2)mv²
U = m*g*h
Where :
m: mass (kg)
v : speed (m/s)
h : hight (m)
Ef - Ei = 0
(K+U)final - (K+U)initial =0
(K+U)final = (K+U)initial
((1/2)mv²+m*g*h)final = ((1/2)mv²+m*g*h)initial , We divided by m both sides of the equation:
((1/2)vB² + g*hB = (1/2 )vA²+ g*hA
(1/2) (vB)² + (9.8)*(14.7) = 0 + (9.8)(26.8 )
(1/2) (vB)² = (9.8)(26.8 ) - (9.8)*(14.7)
(vB)² = (2)(9.8)(26.8 - 14.7)
(vB)² = 237.16

vB = 15.4 m/s : speed of the cart at B
Answer: The principle of conservation of energy, angular speed and centripetal force
Explanation:
At point A, the car experienced maximum of potential energy
As it moves down the hill, the potential energy decreases while the kinetic energy increases.
The maximum kinetic energy of the car is needed for the attainment of enough centripetal force to help the car move through the loop without falling .
Speed can never be negative because it does not depend in which direction the car moves whereas, velocity will change if a car turns from due North to East.
Quantities which can be described only by their magnitudes are called scalars and those which are described by both, magnitude and direction are vectors