Question

A 0.2 kg plastic cart and a 20 kg lead cart both roll without friction on a horizontal surface. Equal forces are used to push both carts forward for a time of 1 s, starting from rest. Is the momentum of the plastic cart greater than, less than, or equal to the momentum of the lead cart?

Answer 1

Answer:

The same

Explanation:

The change in momentum of each cart is equal to the impulse given by the force applied on the cart:

$\Delta p = I = F \Delta t$

where

F is the force applied

$\Delta t$ is the time during which the force is applied

The force applied to both carts (F) is the same, as well as the time ($\Delta t$). This means that the change in momentum, $\Delta p$, is the same for both carts. But both carts start from rest (momentum = 0): this means that at the end, both carts will have exactly same momentum.