A98.0 n grocery cart is pushed 12.0 m along an aisle by a shopper who exerts a constant horizontal force of 40.0 n. if all frictional forces are neglected and the cart starts from rest, what is the grocery cart's final speed?

9.8 m/s

Explanation:

The work done by the force pushing the cart is equal to the kinetic energy gained by the cart:

where

W is the work done

is the final kinetic energy of the cart

is the initial kinetic energy of the cart, which is zero because the cart starts from rest, so we can write:

But the work is equal to the product between the pushing force F and the displacement, so

So, the final kinetic energy of the cart is 480 J. The formula for the kinetic energy is

(1)

where m is the mass of the cart and v its final speed.

We can find the mass because we know the weight of the cart, 98.0 N:

Therefore, we can now re-arrange eq.(1) to find the final speed of the cart:

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