Answer:
change in kinetic energy of the trolley is 53.91 J.
Explanation:
mass of the trolley, m = 5.0 kg
initial velocity of the trolley, u = 1.0 m/s
external force on the trolley, F = 25 N
time of force action, t = 0.75 s
The final velocity of the trolley at the end of 0.75 s is calculated as follows;
![F = \frac{m(v-u)}{t} \\\\25 = \frac{5(v-1)}{0.75}\\\\5(v-1) = 18.75\\\\v-1 = \frac{18.75}{5} \\\\v-1 = 3.75\\\\v = 4.75 \ m/s \ in \ the \ direction \ of \ the \ applied \ force](https://tex.z-dn.net/?f=F%20%3D%20%5Cfrac%7Bm%28v-u%29%7D%7Bt%7D%20%5C%5C%5C%5C25%20%3D%20%5Cfrac%7B5%28v-1%29%7D%7B0.75%7D%5C%5C%5C%5C5%28v-1%29%20%3D%2018.75%5C%5C%5C%5Cv-1%20%3D%20%5Cfrac%7B18.75%7D%7B5%7D%20%5C%5C%5C%5Cv-1%20%3D%203.75%5C%5C%5C%5Cv%20%3D%204.75%20%5C%20m%2Fs%20%5C%20in%20%5C%20the%20%5C%20direction%20%5C%20of%20%5C%20the%20%5C%20applied%20%5C%20force)
The change in kinetic energy of the trolley is calculated as;
Δ K.E = ¹/₂m(v² - u²)
Δ K.E = ¹/₂ x 5(4.75² - 1²)
Δ K.E = 53.91 J.
Therefore, change in kinetic energy of the trolley is 53.91 J.