6.5 CHAPTER 6. MOTIONIN TWO DIMENSIONS
The pilot flies at the same altitude at a constant speed of 130 km.h−^1
relative to the air throughout this flight.
(a) Determine the magnitude of the pilot’s resultant velocity from the
town A to the village B.
(b) How far is village Bfrom town A?
(c) What is the plane’s speed relative to the ground as it travels from
village B to the dam at C?
(d) Determine the following, by calculation or byscale drawing:
i. The distance from thevillage B to the dam C.
ii. The displacement from the dam C back hometo town A.
- A cannon (assumedto be at ground level) isfired off a flat surface at
an angle, θ above the horizontal with an initial speed of v 0.
(a) What is the initial horizontal component of the velocity?
(b) What is the initial vertical component of thevelocity?
(c) What is the horizontal component of the velocity at the highest
point of the trajectory?
(d) What is the verticalcomponent of the velocity at that point?
(e) What is the horizontal component of the velocity when the pro-
jectile lands?
(f) What is the vertical component of the velocity when it lands?
- [IEB 2004/11 HG1] Hailstones fall vertically on the hood of a car
parked on a horizontal stretch of road. The average terminal velocity
of the hailstones as theydescend is 8,0 m.s−^1 and each has a mass of
1,2 g.
(a) Calculate the magnitude of the momentumof a hailstone just
before it strikes the hoodof the car.
(b) If a hailstone rebounds at 6,0 m.s−^1 after hitting the car’s hood,
what is the magnitude of its change in momentum?
(c) The hailstone is in contact with the car’s hood for 0,002 s during
its collision with the hood of the car. What is the magnitude of
the resultant force exerted on the hood if the hailstone rebounds
at 6,0 m.s−^1?
(d) A car’s hood can withstand a maximum impulse of 0,48 N·s with-
out leaving a permanent dent. Calculate the minimum mass of
a hailstone that will leave a dent in the hood ofthe car, if it falls
at 8,0 m.s−^1 and rebounds at 6,0 m.s−^1 after a collision lasting
0,002 s.
- [IEB 2003/11 HG1- Biathlon] Andrew takes part in a biathlon race
in which he first swimsacross a river and thencycles. The diagram
below shows his pointsof entry and exit fromthe river, A and P,
respectively.
