Answer:
(a) 
(b)
Explanation:
It is given that,
Force acting on the particle, F = 12 N
Displacement of the particle, 
Magnitude of displacement, 
(a) If the change in the kinetic energy of the particle is +30 J. The work done by the particle is given by :

is the angle between force and the displacement
According to work energy theorem, the charge in kinetic energy of the particle is equal to the work done.
So,



(b) If the change in the kinetic energy of the particle is (-30) J. The work done by the particle is given by :


Hence, this is the required solution.
When you exert a force on the coin, it will accelerate. If you push the coin and it moves at a constant velocity, the friction force must be equal to the force that you are exerting. This is an example of a balanced force. When the net force is greater than 0 N, the is an unbalanced force.
Glad you are coming back tomorrow I am so happy to be with you guys I will
Lots of reasons. one reason i lie alot (a very bad habit) is im scared of what will happen if i tell the truth. the truth is always better, though.
Wait what is m/s?
Can you tell me that so i could help