At the local grocery store, you push a 14.0-kg shopping cart. You stop for a moment to add a bag of dog food to your cart. With a force of 12.0N, you now accelerate the cart from rest through a distance of 2.30m in 2.55s. What was the mass of the dog food?

Answer 1

Mc = 14 kg = Mass of cart
Md = Mass of dog food.

d = 0.5a*t^2 = 2.30 m.
0.5a*2.55^2 = 2.3
3.25a = 2.3
a = 0.707 m/s^2.

F = M*a
M = F/a
(Mc+Md) = F/a

F = 12 N.
a = 0.707 m/s^2
Solve for Md.