By definition of average acceleration,
<em>a</em> = (20 m/s - 33.1 m/s) / (4.7 s) ≈ -2.78 m/s²
Vertically, the car is in equilibrium, so the net force is equal to the friction force in the direction opposite the car's motion:
∑ <em>F</em> = (1502.7 kg) (-2.78 m/s²) ≈ -4188.38 N ≈ -4200 N
If you just want the magnitude, drop the negative sign.
The statement "<span>The maximum intensity increases, and the peak wavelength decreases."</span> is true regarding how black body radiation changes as the temperature of the radiating object increases. Temperature is directly proportional to intensity but inversely proportional to the wavelength.