Answer:
Force required to accelerate = 794.44 N
Explanation:
Force required = Mass of horse x Acceleration of horse
Mass of horse and rider, m= 572 kg
Acceleration of horse and rider, a = 5 kph per second

Force required = ma
= 572 x 1.39 = 794.44 N
Force required to accelerate = 794.44 N
3 - b) weight decreases
4 -a) 50 kg as mass is same everywhere
5 - b) 200 dynes
Answer:
Acceleration, 
Explanation:
Initial velocity of a particle in vector form, u = (-5i - 2j) m/s
Final velocity of particle in vector form, v = (-6i + 7j) m/s
Time taken, t = 8 seconds
We need to find the magnitude of acceleration vector. The changing of velocity w.r.t time is called acceleration of a particle. It is given by :

or

Hence, the value of acceleration vector is solved.
the above three pictures may help you
go through the attachments
A and c
Because it defines the boundaries of the system