3. A cart (m= 10.0 kg) is currently traveling with a velocity of 3.0 m/s. The cart then gains speed, achieving a new velocity of 7.0 m/s after 8.0 seconds. Calculate the magnitude of the net force acting
on the cart.
A 0.0 N
B. 1.25 N
C. 5.0 N
D. 80N

First we calculate the acceleration of the cart:

a = (v₂ - v₁) / (t)

a = (7 m/s - 3 m/s) / (8 s)

a = 4 m/s / 8 s

a = 0.5 m/s²

Using the Newtons Second Law:

F = m×a

F = (10 kg)(0.5 m/s²)

F = 5 N

when heated, the valance electrons increased their speed and transferred the heat from electron to electron.   i just took the test.