Question

Mr. Starr pushed a cart full of groceries to his car. After emptying the cart, he pushed it back to the store. He pushed the cart at a speed of 2 meters per second each way. Which is the best prediction?(1 point) Responses When it was empty, the cart had less kinetic energy. When it was empty, the cart had less kinetic energy. The cart’s kinetic energy depends on Mr. Starr’s mass. The cart’s kinetic energy depends on Mr. Starr’s mass. The cart had the same kinetic energy going each way. The cart had the same kinetic energy going each way. When it was full, the cart had less kinetic energy.

Answer 1

To determine the best prediction regarding the kinetic energy of the cart, we need to consider the relationship between mass, speed, and kinetic energy. The formula for kinetic energy (KE) is:

\[ KE = \frac{1}{2} mv^2 \]

where \( m \) is the mass and \( v \) is the speed.

1. When the cart is empty:

   • It has a lower mass compared to when it is full.
   • Its speed, however, remains the same at 2 meters per second.

2. When the cart is full:

   • It has a greater mass due to the groceries inside, but the speed is still the same at 2 meters per second.

Since the speed is the same in both cases, we can conclude that when the cart is full, it has more kinetic energy because its mass is greater. Conversely, when the cart is empty, it has less kinetic energy due to its lower mass.

Given these considerations, the best prediction is:

When it was empty, the cart had less kinetic energy.