Final answer:
To find the energy lost to air resistance, calculate the drag force using the truck's drag coefficient, cross-sectional area, air density, and velocity. Then calculate the work done against the drag force over an hour and convert to megajoules.
Step-by-step explanation:
To calculate the energy lost to air resistance per hour by the pickup truck, we first need to determine the drag force. The drag force, Fd, experienced by a vehicle moving through the air is given by the equation:
Fd = ½ × Cd × A × ρ × v2
Where:
Cd is the drag coefficient,
A is the cross-sectional area of the truck,
ρ is the density of the air,
v is the velocity of the truck.
Plugging in the given values:
Fd = ½ × 0.45 × 3.3 m2 × 1.2 kg/m3 × (26.1 m/s)2
Now we calculate the work done against this force over an hour:
Work = Fd × distance
Distance traveled in one hour at a steady speed of 26.1 m/s is:
Distance = velocity × time = 26.1 m/s × 3600 s
After calculating the Work, we convert it to megajoules (MJ):
Energy lost per hour in MJ = Work in joules × 10-6
The exact calculation has been omitted, but it would involve multiplying the drag force by the distance traveled in one hour, and converting the result from joules to megajoules.