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.
1. the insect
because of how fast the car is going and how small they are
Answer:
Ft = 17.48°C
Explanation:
Ft is the final temperature. However, ice absorbs heat during two process of melting and cooling and as such, there is no loss of heat to or from the surrounding hence by conservation of energy.
Therefore,
Heat absorbed by water of 20g = heat rejected by water of 265g.
So; M(ice)[C(ice) [(ΔT) + LH(ice) + C(water)(ΔT)] = C(water) M(water) (ΔT)
So, 20[(2.108) [0 - (-20)] + 333.5 + 4.187(Ft - 0)]] = (285)(4.187) (25 - Ft)
To get;
7513 + 83.74 Ft = 29832.4 - 1193.3 Ft
So factorizing, we get;
83.74 Ft + 1193.3 Ft = 29832.4 - 7513
So; 1277.04 Ft = 22319.4
So; Ft = 22319.4/1277.04 = 17.48°C