Yes it is work because when you throw a ball, you transfer energy to it and it moves.
Well we can just use F=ma. The force is 10N, the mass is 50 kg, solve for a. Well since we kg and N, no conversion is necessary. So just plugging in the numbers, we get
10N = 50 kg · a

A newton is just 

The s^2 and 50 kg you multiply

The kg's cancel and 10/50 is 1/5

So the acceleration is 1/5 m/s^2
The amplitude of wave-c is 1 meter.
The speed of all of the waves is (12meters/2sec)= 6 m/s.
The period of wave-a is 1/2 second.
Answer:
θ = sin⁻¹
Explanation:
From one of the equations of motion, v² = u² + 2as.......... equation 1
Since the object thrown was moving against gravity, then the acceleration, a would change to -g and the initial velocity u would change to V₀ sin θ because the object is travelling at angle of θ to the horizontal. By inputting all these parameter into equation 1, we would arrive at:
v² = (u sin θ)² - 2gd
(u sin θ)² = 2gd
d = (u sin θ)²/2g
sin² θ = 2gd
sin θ = 
θ = sin⁻¹ 