Question

Later, while taking your groceries back to the car, you accidentally let go of your cart. It rolls straight down a grassy slope at a constant speed of 10 m/s. What is the net force on the cart during this motion

Answer 1

Car is moving on the glassy slope with constant speed

Now we know that

$a = \frac{dv}{dt}$

so acceleration is rate of change in velocity

as we know that velocity is constant here so acceleration is zero

so here

$a = 0$

now as we know by Newton's II law

$F = ma$

since a = 0

$F = 0$

so net force will be ZERO on it during this motion