An airplane traveling at 400 mph at a cruising altitude of 7.2 mi begins its descent. If the angle of descent is 1 degree from the horizontal, determine the new altitude after 15 minutes. Round to the nearest tenth of a mile.

New altitude = 5.5 miles

Step-by-step explanation:

We are given;

Velocity = 400 m/h

Angle of descent = 1°

Altitude = 7.2 miles

Time = 15 minutes = 15/60 hours = 0.25 hours

Now, the downward component of its speed is;

Vy = (400) sin (1°)

Vy = 6.98 mph

After a time t, its height will be;

h (t) = (7.2 - 6.98t) miles, for t = hours

We are given; t = 0.25 hrs

Thus;

h (0.25) = 7.2 - (6.98*0.25) miles

h (0.25) = 5.46 miles

h (0.25) ≈ 5.5 miles to the nearest tenth