Answer :
Final answer:
The change in kinetic energy of the truck as it accelerates from 42.6 km/hr to 81.8 km/hr is 49.2 kJ, which is Option D.
Explanation:
To calculate the change in kinetic energy of the truck, we can use the kinetic energy formula: KE = ½mv², where m is the mass of the truck and v is its velocity. The change in kinetic energy is the difference between the final and initial kinetic energies. First, we convert the velocities from km/hr to m/s by multiplying by (1000 m/km) / (3600 s/hr), getting 11.83 m/s (initial) and 22.72 m/s (final).
Initial KE = ½(2490 kg)(11.83 m/s)²
Final KE = ½(2490 kg)(22.72 m/s)²
To find the change in kinetic energy, subtract the initial KE from the final KE:
ΔKE = Final KE - Initial KE
After calculating these values, the change in kinetic energy is found to be 49.2 kJ (Option D).
