Complete Question
The cars of a roller-coaster ride have a speed of 19.0 km/h as they pass over the top of the circular track. Neglect any friction and calculate their speed v when they reach the horizontal bottom position. At the top position, the radius of the circular path of their mass centers is 21 m, and all six cars have the same mass.V = -18 m What is v?X km/h
Answer:

Explanation:
Velocity 
Radius 
initial velocity u
Generally the equation for Angle is mathematically given by




Generally
Height of mass



Generally the equation for Work Energy is mathematically given by

Therefore



Answer:
Resistor B
Explanation:
Since resistance is the opposition to the flow of current in a circuit,
first let assume the two resistors are connected in parallel to the voltage, recall that when connection is in parallel, the different amount of current pass through the resistors depending on the value with the small resistor having a lower resistance effect hence higher current will pass through
The energy dissipated in each resistor can be calculated as
.
from the formula we can conclude that the energy value will be higher for the resistor with small resistance value. hence more heating effect which will cause it to be warm.
Also when connected individually the current flow from the voltage source will pass through the resistor which when we calculate the energy dissipated, the resistor with smaller value will be higher because it will draw more current which will in turn lead to a heating effect and cause the resistor to be warm. Hence we can conclude that the resistance B has greatest resistance value.
Answer:
|W|=169.28 KJ/kg
ΔS = -0.544 KJ/Kg.K
Explanation:
Given that
T= 100°F
We know that
1 °F = 255.92 K
100°F = 310 .92 K

We know that work for isothermal process

Lets take mass is 1 kg.
So work per unit mass

We know that for air R=0.287KJ/kg.K


W= - 169.28 KJ/kg
Negative sign indicates compression
|W|=169.28 KJ/kg
We know that change in entropy at constant volume


ΔS = -0.544 KJ/Kg.K