Final answer:
The expression used to determine the magnitude of impulse on an object is F⋅Δt, representing the force multiplied by the time interval over which it is applied.
Step-by-step explanation:
The expression that can be used to determine the magnitude of the impulse on an object is F⋅Δt. Impulse, denoted as J, is defined as the product of the force F(t) applied to an object and the time interval dt over which it acts, which can be expressed mathematically as J = ∫ F(t)dt. However, when the force is constant over the time interval Δt, the impulse can be simplified to J = F⋅Δt, where F is the constant force and Δt is the time interval during which the force is applied. The product of these two quantities gives the change in momentum of the object, or the impulse.