This ain’t mine but here is someone else’s
a. 46 m/s east
The jet here is moving with a uniform accelerated motion, so we can use the following suvat equation to find its velocity:

where
v is the velocity calculated at time t
u is the initial velocity
a is the acceleration
The jet in the problem has, taking east as positive direction:
u = +16 m/s is the initial velocity
is the acceleration
Substituting t = 10 s, we find the final velocity of the jet:
And since the result is positive, the direction is east.
b. 310 m
The displacement of the jet can be found using another suvat equation
where
s is the displacement
u is the initial velocity
a is the acceleration
t is the time
For the jet in this problem,
u = +16 m/s is the initial velocity
is the acceleration
t = 10 s is the time
Substituting into the equation,

Answer:
d. None of the above.
Explanation:
In a parabolic motion, you have that in the complete trajectory the component velocity is constant and the vertical component changes in time. Then, the total velocity vector is not zero.
In the complete trajectory the gravitational acceleration is always present. Then, the grasshopper's acceleration vector is not zero.
At the top of the arc the grasshopper is not at equilibrium because the gravitational force is constantly acting on the grasshopper.
Then, the correct answer is:
d. None of the above.
Kinetic energy is related to velocity by:
KE = (1/2)mv^2
solve for mass m
10 = (1/2)m(10)^2
10 = (1/2)m(100)
10= 50m
10/50 = m
1/5 = m
at 20 km/hr
KE = (1/2)(1/5)(20)^2
KE = (1/10)(400)
KE = 40 J