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     The window sill is 35.0m above the sidewalk where Milly is standing directly below the falling pot.  Milly is 1.05m tall, her ears are 5.00cm below her head, and she needs 0.400s to respond to the warning.  The speed of sound in air is 340m/s.  What is the minimum height of the pot above ground at the instant Willy shouts his warning if Milly is to avoid being "potted"?  Answer in metres.

Answer

     A large circus carousel ride in Mexico City has gondolas suspended by ropes spinning in a circle.  they are 5m from the ground and are moving around in a circle of radius 15m once every 8 seconds.  A rope breaks holding the gondola containing Senator Andrew Thompson, so he loses his seat.  How far in meters from the center of the carousel does the gondola first hit the ground?

Answer

1.     The acceleration of gravity on the surface of Mars is 3.72m/s² .  Mars has a diameter of 6790km, and it's period of revolution is 24.72 hours, a bit longer than an Earth day.  How far from the center Mars does a satellite need to be positioned in the equatorial plane so that it remains stationary to an observer on that planet?  We might call it a "Marosynchronous" satellite.  You may assume that the strength of gravity from a planet is inversely proportional to the square of the distance from it's center.  Answer in km.

Answer

2.     A Tim Hortons server takes a 1-litre carafe of very hot water at 90 C from a defective coffee-making machine.  How much water at 25 C must she mix with this hot water to make the mixture drinkable at 65 C?  Answer in cm³.  1 litre = 1000cm³.  the specific heat of water is essentially independent of temperature, and you may ignore the specific heat of the vessels.

Answer: E

3.     An astronaut on the dark side of the Earth takes a flash picture of a small piece of debris floating 5.0m from the space shuttle.  When the object has drifted away to a distance of 30m, but with the same orientation, he takes another picture with the same lens setting and flash power.  What is the ratio of the number of photons (that is, the amount of light) received by the camera in the second picture of the number receive in the first picture?  You may assume that light spreads out from the flash and the piece of debris in the usual way.

Answer: E

4.     Sheila Copps is still driving her sturdy 2200kg car from the 2003 SIN exam, but this time when she sees Prime Minister Paul Martin stopped in his 1500kg car, she rams into the back of him!  She is traveling at 30km/hr on impact, and just after the collision Martin's car is crushed in at the back by the crash, but Sheila's car does not suffer any damage.  How much is Martin's car shortened by the "accident", assuming that a constant force of 50000N is required to crush it?  You may assume that the kinetic energy lost by the cars during the brief collision goes into the crushing process.

5.     On a second honeymoon, Romeo and Juliet (without the kids) drive on main roads at 100km/hr for a total of 3 hours, and at an average of 60km/hr through built-up areas for another 7 hours.  What is the average speed in km/hr for the entire trip?

Answer: C

6.     The length of the course is 100m.  In the first race, Willy's adversary, Donny, crosses the finishing line when Willy is a distance of 20m behind him.  In the second reace, Donny, being a good sport, starts 20m behind Willy, who is on the 100m starting line.  If they each run at the same constant speed as in the first race, find the ratio, r, of the times to reach the finishing line, and hence dertermine the outcome of the second race: r=t(Donny)/t(Willy).

Answer: A

7.     A 25000kg softwood lumber truck with poor brakes (BC loggers are still short on cash...) is coming down a hill 150m high.  At the top its speed is 50km/hr.  the only significant frictional forces retarding its motion are the brakes.  When the truck finally is at the bottom of the hill, it is moving at 130km/hr.  How much energy in joules was dissipated by the brakes?

Answer: B

a² = b² + c² - 2bc cos(f)

Answer: A

9.     A teenager and his skateboard have a total mass of 80kg.  he is moving at 7.5m/s on frictionless ice and grabs a rope suspended from a park pole as shown in the diagram, and hangs on.  His speed remains the same as he goes into a circular turn of radius 5m, with the rope at a 30  angle from the horizontal.  The tension in the rope is the only force responsible for his circular motion, since he is on ice during the circular motion.  With what force in newtons does his skateboard press down on the smooth, level ice?

Answer: D

10.     In a high-school physics contest, a small toy cannon uses a spring with force constant 147N/m compressed by 20cm to shoot marbles down the hall.  The ceiling has a height of 3.0m, the marbles have a mass of 30grams, and the cannon is fixed on the floor.  What is the farthest distance the cannon can shoot the marble if it must not hit the ceiling?  Ignore air resistance.  Answer in meters.

Answer: E

11.     A 1200kg police car in a chase starts from rest and accelerates for 250m, reaching a speed of 140km/hr.  It then travels at that speed for 22 seconds.  The the policewoman applies the brakes and stops quickly with uniform deceleration in 8 seconds.  What is the total distance traveled in meters?

Answer: B

12.     In the game of billiards, all balls have the same mass and size, and they experience collisions that are perfectly elastic, essentially conserving mechanical energy.  A player shoots the cue ball towards two balls that are in contact, striking them simultaneously.  If the cue ball has speed V₀, what is its speed after the collision?  Assume the balls are smooth so that forces can only act along the line joining their centers.

Answer: C

13.     A rebellious teenager in his turbo-powered car of total mass 1500kg is going over the top of a hill on the road of radius 90m.  the car is moving at 80km/hr, and accelerating forward at 2.5m/s².  What is the magnitude of the total force of the road on his car in newtons?

Answer: B

14.     The new liberal government in Ontario wants to replace all coal-fired power plants by 2007.  Let's be really optimistic and say they get it done by 2009.  Presently these can supply up to 7500MW of power.  Suppose these plants supply on average 5000MW in the five years before they are decommissioned.  How many metric tones of coal will be needed over this period? 1 tone = 1000kg.  A kg of coal has an energy content of about 3.2x10⁷ joules.  A fossil-fuel plant has an overall efficiency of about 40%.  A year has 365 days.

Answer: B