At 2:00 p. m. a car's speedometer reads 30 mi/h. At 2:30 p. m. it reads 50 mi/h. Show that at some time between 2:00 and 2:30 the acceleration is exactly 40 mi/h2.

The acceleration is exactly 40 mi/h² as shown

Explanation:

Given;

initial velocity of the car, u = 30 mi/h

final velocity of the car, v = 50 mi/h

change in velocity, ΔV = v - u

                               ΔV = 50 mi/h - 30 mi/h = 20 mi/h

initial time, t₁ = 2:00 PM

final time, t₂ = 2:30 PM

Change in time, Δt = t₂ - t₁

                           Δt = 2: 30 - 2:00 = 30 mins  = 0.5 hour

Acceleration is given as change in velocity per change in time;

a = ΔV /  Δt

Therefore, the acceleration is exactly 40 mi/h² as shown.

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the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia