Wind Problem — IISER Physics MCQs with Solutions
Free IISER Physics Wind Problem MCQs with step-by-step solutions (20 questions). Part of Motion in 2D. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Wind Problem · easy · numerical
A drone flies with an airspeed of 21 m/s and a tailwind of 9 m/s blows in its direction of motion. What is the drone’s speed over the ground?
A. 30 m/s ✓ Correct
B. 24 m/s
C. 12 m/s
D. 21 m/s
Solution: With a tailwind the speeds add: v(ground) = 21 + 9 = 30 m/s.
Q2 — Wind Problem · easy · numerical
A glider moves with an airspeed of 28 m/s directly into a headwind of 16 m/s. What is its ground speed?
A. 20 m/s
B. 32 m/s
C. 12 m/s ✓ Correct
D. 44 m/s
Solution: Against a headwind the speeds subtract: v(ground) = 28 − 16 = 12 m/s.
Q3 — Wind Problem · easy · numerical
A seabird flies due north with an airspeed of 30 km/h while a wind blows due east at 16 km/h. What is the bird’s speed relative to the ground?
A. 46 km/h
B. 34 km/h ✓ Correct
C. 25 km/h
D. 14 km/h
Solution: The velocities are perpendicular: v(ground) = √(30² + 16²) = √1156 = 34 km/h.
Q4 — Wind Problem · easy · numerical
A drone is pointed due north with an airspeed of 16 m/s while a steady wind blows due east at 12 m/s. At what angle east of north does the drone actually track over the ground?
A. tan⁻¹(3/4) ≈ 37° east of north ✓ Correct
B. 30° east of north
C. 45° east of north
D. tan⁻¹(4/3) ≈ 53° east of north
Solution: tanθ = v(wind)/v(air) = 12/16 = 3/4, so the track is deflected θ = tan⁻¹(0.75) ≈ 37° east of north.
Q5 — Wind Problem · easy · numerical
A small plane with an airspeed of 280 km/h flies a 700 km route with a direct tailwind of 70 km/h. How long does the flight take?
A. 2.5 h
B. 1.5 h
C. 2 h ✓ Correct
D. 3 h 20 min
Solution: Ground speed = 280 + 70 = 350 km/h, so t = 700/350 = 2 h.
Q6 — Wind Problem · easy · numerical
A drone that flies at 25 m/s (airspeed) must track straight along a line while a wind of 15 m/s blows perpendicular to that line. At what angle into the wind must the drone be headed? (sin 37° = 0.6)
A. 53° into the wind from the intended track
B. 45° into the wind from the intended track
C. 30° into the wind from the intended track
D. 37° into the wind from the intended track ✓ Correct
Solution: To cancel the crosswind, sinθ = v(wind)/v(air) = 15/25 = 0.6 ⇒ θ = 37° into the wind.
Q7 — Wind Problem · easy · numerical
A bird with an airspeed of 26 km/h angles into a 10 km/h crosswind so that it tracks straight along its intended line. What is its speed along that line (ground speed)?
A. 16 km/h
B. 28 km/h
C. 36 km/h
D. 24 km/h ✓ Correct
Solution: Ground speed = √(v(air)² − v(wind)²) = √(26² − 10²) = √576 = 24 km/h.
Q8 — Wind Problem · easy · numerical
A drone has an airspeed of 35 m/s. Heading suitably into a wind that blows perpendicular to its intended track, it manages a ground speed of only 28 m/s along the track. What is the wind speed?
A. 45 m/s
B. 7 m/s
C. 21 m/s ✓ Correct
D. 63 m/s
Solution: From the right triangle, v(wind) = √(v(air)² − v(ground)²) = √(35² − 28²) = √441 = 21 m/s.
Q9 — Wind Problem · medium · numerical
A drone with an airspeed of 20 m/s flies from its base to a station 600 m directly downwind and returns, with a steady wind of 10 m/s along the line. What is the total time for the round trip?
A. 40 s
B. 80 s ✓ Correct
C. 60 s
D. 100 s
Solution: Outbound: 600/(20 + 10) = 20 s; return: 600/(20 − 10) = 60 s; total = 80 s (more than the 60 s needed in still air).
Q10 — Wind Problem · medium · numerical
A migrating bird flies with an airspeed of 10 m/s while a 6 m/s wind blows at 60° to the bird’s heading (partly helping it). What is the bird’s speed over the ground?
A. 4 m/s
B. 16 m/s
C. ≈ 11.7 m/s
D. 14 m/s ✓ Correct
Solution: By the cosine rule for addition, v² = 10² + 6² + 2 × 10 × 6 × cos 60° = 100 + 36 + 60 = 196, so v = 14 m/s.
Q11 — Wind Problem · medium · numerical
A balloon rises vertically at 9 m/s while a horizontal wind carries it sideways at 12 m/s. What is the balloon’s resultant speed?
A. 3 m/s
B. 8 m/s
C. 15 m/s ✓ Correct
D. 21 m/s
Solution: The components are perpendicular: v = √(9² + 12²) = √225 = 15 m/s.
Q12 — Wind Problem · medium · numerical
A balloon ascends steadily at 5 m/s while a horizontal wind of 9 m/s blows throughout. How far has the balloon drifted horizontally by the time it reaches a height of 200 m?
A. 360 m ✓ Correct
B. 450 m
C. 200 m
D. 160 m
Solution: Time to rise: t = 200/5 = 40 s; horizontal drift = 9 × 40 = 360 m.
Q13 — Wind Problem · medium · numerical
A ferry sails due north at 12 km/h while the true wind blows at 16 km/h from the east (perpendicular to the ferry’s motion). What wind speed is felt on the ferry’s deck?
A. 10.6 km/h
B. 4 km/h
C. 20 km/h ✓ Correct
D. 28 km/h
Solution: Apparent wind = true wind − ferry velocity; the perpendicular components give √(16² + 12²) = √400 = 20 km/h.
Q14 — Wind Problem · medium · numerical
A drone pointed due north with an airspeed of 20 m/s is observed to track 37° east of north because of an easterly-blowing wind. What is the wind speed? (tan 37° = 3/4)
A. 25 m/s
B. 12 m/s
C. 15 m/s ✓ Correct
D. 26.7 m/s
Solution: tan 37° = v(wind)/v(air) ⇒ v(wind) = 20 × 3/4 = 15 m/s.
Q15 — Wind Problem · medium · numerical
A drone with an airspeed of 15 m/s must travel 720 m along a straight line while a 9 m/s wind blows perpendicular to the line. Heading correctly into the wind, how long does the trip take?
A. 40 s
B. 80 s
C. 60 s ✓ Correct
D. 48 s
Solution: Ground speed along the line = √(15² − 9²) = √144 = 12 m/s, so t = 720/12 = 60 s.
Q16 — Wind Problem · medium · numerical
A plane covers 480 km in 2 hours while flying directly into a steady headwind of 30 km/h. What is the plane’s airspeed?
A. 240 km/h
B. 210 km/h
C. 300 km/h
D. 270 km/h ✓ Correct
Solution: Ground speed = 480/2 = 240 km/h; airspeed = ground speed + headwind = 240 + 30 = 270 km/h.
Q17 — Wind Problem · medium · numerical
A drone is pointed due north with an airspeed of 28 m/s while a wind blows due east at 21 m/s. What is the magnitude of the drone’s displacement after 10 s?
A. 280 m
B. 490 m
C. 350 m ✓ Correct
D. 210 m
Solution: In 10 s it moves 280 m north and 210 m east; displacement = √(280² + 210²) = √122500 = 350 m.
Q18 — Wind Problem · medium · numerical
On the same straight route, a plane’s ground speed is 240 km/h with the wind and 180 km/h against the same wind (equal airspeed both ways). What is the wind speed?
A. 15 km/h
B. 210 km/h
C. 60 km/h
D. 30 km/h ✓ Correct
Solution: v(wind) = (with − against)/2 = (240 − 180)/2 = 30 km/h (the airspeed is the average, 210 km/h).
Q19 — Wind Problem · medium · numerical
An aircraft with an airspeed of 28 m/s must fly straight along a track while a 14 m/s wind blows perpendicular to the track. At what angle to the track must the nose be pointed into the wind?
A. 30° ✓ Correct
B. 60°
C. 45°
D. 37°
Solution: sinθ = v(wind)/v(air) = 14/28 = 0.5 ⇒ θ = 30° into the wind.
Q20 — Wind Problem · medium · numerical
A microlight aircraft with an airspeed of 125 km/h must fly 300 km due north while a 75 km/h wind blows from the west (perpendicular to the route). Heading correctly into the wind, how long does the flight take?
A. 3 h ✓ Correct
B. 2.4 h
C. 4 h
D. 1.5 h
Solution: Ground speed along the route = √(125² − 75²) = √10000 = 100 km/h, so t = 300/100 = 3 h.