A worker exerts a 140 N horizontal force on a 41 kg crate. The crate's acceleration across a level floor is 0.90 m/s2. Find the frictional force that the floor exerts on the crate.

To find the frictional force that the floor exerts on the crate, we need to use Newton's second law of motion, which states that the net force acting on an object is equal to the product of its mass and acceleration.

In this scenario, the horizontal force exerted by the worker on the crate is the net force, as there are no other forces mentioned. So, we have:

Net force = 140 N

Mass of the crate, m = 41 kg

Acceleration of the crate, a = 0.90 m/s²

According to Newton's second law, net force = mass × acceleration:

140 N = 41 kg × 0.90 m/s²

To find the frictional force, we need to calculate the force due to acceleration, which is the product of mass and acceleration:

Force due to acceleration = mass × acceleration

Force due to acceleration = 41 kg × 0.90 m/s²

Force due to acceleration = 36.9 N

Now that we have the force due to acceleration, we can subtract it from the total net force to find the frictional force:

Frictional force = Net force - Force due to acceleration

Frictional force = 140 N - 36.9 N

Frictional force = 103.1 N

Therefore, the frictional force that the floor exerts on the crate is 103.1 N.