Sorry to say but I know that t(e introduction is first and the coda is last
Explanation:
It is given that,
Total mass is 70 kg
The truck exerts a constant force of 20 N.
Then the net force is given by :
F = ma
a is acceleration of rider

Initial velocity of rider is 0. So, using equation of kinematics to find the final velocity as :

Since, 1 m/s = 2.23 mph
4.28 m/s = 9.57 mph
So, the speed of the rider is 4.28 m/s or 9.57 mph.
Answer:
C. It is negative
Explanation:
Per Newton's second law, the net force is the mass times the acceleration:
∑F = ma
If the acceleration is negative, the net force is negative.