Final answer:
The force of 800N causes the fullback's velocity to change by 10 m/s.
Step-by-step explanation:
The force of 800N causes the fullback's velocity to change by 10 m/s. Given the mass of the fullback as 80 kg, we can use Newton's second law to calculate the acceleration experienced by the fullback.
Using the equation F = ma, where F is the force, m is the mass, and a is the acceleration, we can rearrange the equation to solve for acceleration:
a = F/m = 800N / 80kg = 10 m/s².
So, the acceleration of the fullback is 10 m/s².