Answer:
a = 7.35 ft / s²
Explanation:
For this exercise we must use the kinematics relations
x = v₀ t + ½ a t²
as the runner leaves the starting line his initial velocity is zero
x = ½ a t²
a =
let's reduce the distance to foot
x = 60 yd (3ft / 1yd) = 180 ft
let's calculate
a = 2 180 / 7²
a = 7.35 ft / s²
Answer:
(a) Magnitude of force is 262.51 N
(b) Angle with East direction is 
Explanation:
Force by Jack in vector form
Force by Jill in Vector form is given by

Force by Jane is

Net force is:

Hence

The net force will be given by

Since
and 

The direction of net force is:

Since
and

The angle with East direction is 
Net force exerted on the donkey is in the south-east direction. So, the angle of net force from the east direction is
and it is
from the south.
It can also be called the thermal kinetic energy. The internal energy of a system is the total thermal kinetic energy and thermal potential energy of all its atoms and molecules. The Kinetic Theory of Matter is explains the kinetic energy of particles in an object.