A physics professor lifts her 9.0-kg briefcase at constant speed with an upward force. Find the magnitude of her force.

No acceleration.

Applied Force = Weight = M g

To find the magnitude of the force exerted by the professor, we need to consider the force needed to counteract the force of gravity acting on the briefcase.

The force of gravity on an object can be calculated using the formula:

F_gravity = mass × acceleration due to gravity

In this case, the mass of the briefcase is given as 9.0 kg, and the acceleration due to gravity is approximately 9.8 m/s^2.

So, F_gravity = 9.0 kg × 9.8 m/s^2 = 88.2 N

Since the professor lifts the briefcase at a constant speed, the force she exerts must be equal in magnitude but opposite in direction to the force of gravity. Therefore, the magnitude of the professor's force is also 88.2 N.