- #1

Cummings

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2 question that bug me at the moment.

1.

A plane is flying due south at 100m/s on an initially still day. Then a crosswind with a velocity of 25m/s towards the west beings to blow.

- What is the velocity of the plane under the influence of this crosswind?

- In which direction should the pilot steer the plane to maintain a velovity of 100m/s south?

I used a simple vector sum:

vplane = 100

vair = 25

vsum = square root((vplane^2)+(vair^2))

i got vsum = 103.08m/s

and the direction is South 14Degrees West.

I think thats right, the answer states its 10^3 ..but i think they accidentely put the 3 as a power. 10^3 not 103

2.

A car travelling with a constant speed of 80 km/h passes a stationary motercycle policeman. The policeman sets off in pursuit, acceserating to 80km/h in 10s and reaching a contstant speed of 100km/h after a further 5s. At what time will the policeman catchup with the car?

This question really made me think of last years studies, but i couldnt get my head around it. After the 15 seconds i can find out how far the car and policemen have traveled, but cant figure it out further.

Thanks for your time,

Cummings

Cummings@softhome.net