What factor of motivation causes people to work for their own enjoyment, not for the rewards work may bring

Sometimes people are motivated to act because of internal desires and wishes, but at other times, behaviors are driven by a desire for external rewards. ... The incentive theory is one of the major theories of motivation and suggests that behavior is motivated by a desire for reinforcement or incentives

#Hope it helps

a. formula: f=ma or f/m=a

10,000n/1,267kg≈7.9m/

b. formula: a= and s=d/t

speed= 394.6/15

s=26.3m/s

a=

a=1.75m/

c. 7.9-1.75=difference of 6.15m/

d. the force that most likely caused this difference is friction forces

which sentences ? that question is incomplete