A 15-kilogram cart is at rest on a horizontal

surface. A 5-kilogram box is placed in the cart.

Compared to the mass and inertia of the cart, the

cart-box system has

(1) more mass and more inertia

(2) more mass and the same inertia

(3) the same mass and more inertia

(4) less mass and more inertia

The most likely answer to this problem would be (1) more mass and more inertia.

A 15-kilogram cart at rest and a 5-kilogram box would make up a 20-kilogram cart and box that is at rest on a horizontal surface. The mass changed into something more, of course, as a result of combining the two object into one and by combining the two objects' mass, the inertia that it previously possessed as a cart by itself was increased when the inertia of the box was also combined to the cart.