What work needs to be done to accelerate a four-wheeled cart to a speed of V = 4 m / s. Trolley weight with wheels

What work needs to be done to accelerate a four-wheeled cart to a speed of V = 4 m / s. Trolley weight with wheels M = 30 kg. The mass of each wheel is concentrated on the rim and is equal to m = 2.5 kg. Hint: take into account that the kinetic energy of a body is made up of the kinetic energy of its translational motion, and the kinetic energy of the rotational motion of its parts.

The work expended is determined by the kinetic energy of the cart. Let’s use the well-known formula:

E = m * v ^ 2/2.

After acceleration, the trolley acquires energy:

E1 = 30 * 4 ^ 2/2 = 240 J.

To spin each wheel you will need:

E2 = 2.5 * 4 ^ 2/2 = 20 J.

Since there are four wheels from the total perfect work, it will be equal to:

240 + 4 * 20 = 320 J.

Answer: the required work is 320 J.