The length of the track itself is 500m. The vehicles (each of mass 15kg) are dragged along the track back to the top of the ride in stacks of 4. The force required to drag
them at constant speed is 200N
Use an equation from page 2 to calculate the total work done in dragging the stack
back to the start of the ride

In a good thermo flask the main cause of heat loss is

The law of the conservation of momentum says that the total momentum of any closed and isolated system cannot

Acarpenter builds an exterior house wall with a layer of wood 2.9 cm thick on the outside and a layer of styrofoam insulation 2.3 cm thick on the inside wall surface. the wood has k=0.080w/(m⋅k), and the styrofoam has k= 0.010 w/(m⋅k). the interior surface temperature is 19.0 ∘c , and the exterior surface temperature is -15.0 ∘c . a.)what is the temperature at the plane where the wood meets the styrofoam? celsius b.)what is the rate of heat flow per square meter through this wall? /m^2