A series of questions from Edinburgh University's Physics Skills papers

Road Safety

A chicken is waiting to cross a 5m, one way road, along which cars are travelling

at 40m/s. If the chicken can accelerate at 5m/s2 to a maximum speed of

5m/s, how big a gap in the traffic does she require in order to cross the road

without a car passing her during the crossing.

Death wish

Depressed by its inability to solve physics problems, a chicken decides in end it

all in the traditional way. A bus will pass at precisely 12 o’clock, on a road parallel

to the field edge, which is 100m from the coop at the closest point. The bus

travels at 10m/s, and the chicken can run at 5m/s. What is the latest time that

the chicken can exit the coop?

Why don't penguin's feet freeze?

Some Chickens are cooler than others

A large frozen chicken at -10 C is dropped into a pot containing an equal mass

of brine at 0C. After some time, the chicken has not thawed. What temperature

is the chicken, and what fraction of the chicken melts.

[Assume the brine has a freezing point of -15C and heat capacity of 3.2kJ/kg/K,

independent of concentration. Treat the chicken as water ice with heat capacity

2kJ/kg/K, latent heat of melting 334kJ/kg]

Though not for long

Unscheduled Pantechnion Incident

A farmer wishes to measure the width of a road. He releases a flock of 100

chickens simultaneously from one side of the road. These chickens are known

to cross roads directly at an average speed of 1m/s and standard deviation of

0.2m/s. after 5 seconds the experiment is abruptly ended by the sudden arrival

of a large lorry, at which point only 17 chickens have crossed the road.

Estimate the width of the road, and the error on your estimate.

Ruffled Feathers

A coop is demolished to make way for a 5MW wind turbine. One of the chickens flies

into space where it is annihilated in an unfortunate encounter with an antimatter

antichicken. How long does the wind turbine have to operate to generate the equivalent

amount of energy?

Bottom of Form

In a flap

A closed 1 tonne lorry is carrying 500kg of chickens to market. It has to cross a bridge

which can bear a maximum weight of 1.2tonnes. The driver attempts to lighten the load

by getting the chickens to fly up. Will this help?

Getting over it.

50 chickens are walking across a 10m wide icy road at 2m/s. Being cautious birds, they leave enough gap

between one another to stop at a deceleration rate of 1m/s^2. How long does it take them all to cross?

On their return, enthused by the prospect of a feed, they decide to run across, at 5m/s again leaving

enough space to stop. Now how long does it take them?

McChicken

A spacechicken finds itself on the moon. How many chicken sandwiches contain enough energy to put it into orbit?

[ A typical chicken sandwich has 385 nutritional calories. One nutritional calorie is equivalent to an energy of 4.2 kJ. The radius and mass of the moon are 1738 km and 7.34 x 10²² kg respectively.]