thermal expansion of gap and gaas (chapter 1, problem 17). gap has the zinc blende structurc. thc lincar cxpansion cocfficicnt in gap has been mcasurcd as follows: n= 4.65x10-6 k-1 at 300 k; 5.27x 10-6 k-1 at 500 k; 5.97x10-6 k-1 at 800 k. (a) calculate the coefficients a, b and c in dl λ(t)-a+b(7-1.)+c(7-「)2 + . . , where to-300 k. (3 marks) (b) the lattice constant of gap, a, at 27 °c is 0.5451 nm. calculate the lattice constant at 300 °c. (3 marks) (c) the linear expansion coefficient of gaas over 200 k-1000 k is given by, λ-4.25x10-6 + (5.82x 10-9 )t-(2.82x10-12 )t2 where t is in kelvins. the lattice constant a at 300 k is 0.56533 nm. calculate the lattice constant and the density at -40 °c. (4 marks)

I'm kinda lost ! 1. when marilyn takes her pet dog for a walk, the dog walks at a veryconsistent pace of 0.55 m/s. draw a position-time graph to representmarilyn's dog walking the 19.8 m distance from the front of her house tothe nearest fire hydrant.2. both car a and car bleave school when a stopwatch reads zero. car atravels at a constant 75 km/h, and car b travels at a constant 85 km/h.a) draw a position-time graph showing the motion of both cars. howfar are the two cars from school when the stopwatch reads 2 hrs? calculate the distances and show them on your graph.b) both cars passed a gas station 120 km from the school. when dideach car pass the gas station? calculate the times and show themon your graph.3. the figure below shows the position-time graph showing a shopper'smovement up and down the aisle at a store.a) write a story describing the shopper's movements at the store.b) when does the shopper have a position of 6 m? c) how much time passes between when the shopper enters the aisleand when he gets to a position of 12 m? what is the shopper's averagevelocity between 37 s and 46 s?

Which statements about tornadoes are true? check all that apply. (a) about 12,000 tornadoes hit the united states every year. (b) a tornado looks like a funnel. (c) tornadoes are deadly atmospheric storms that cause millions in damages each year. (d) tornadoes can reach wind speeds of more than 300 miles per hour. (e) kansas is the state with the most tornadoes. (f) you will always notice a funnel before a tornado strikes.

Thomas his older brothers, who own a junk yard, on the weekends to earn extra money. he likes to them push broken-down cars to the back of the junk yard because it makes him feel strong. last saturday, they pushed three cars with different weights, and he noticed he used different amounts of force for each one. the cars were the following weights: white car: 2,700 kg red car: 1,500 kg blue car: 2,100 kg think about how much force is needed to move each car. which correctly lists the cars in order from the most to least amount of force needed to move them? a) white, blue, red b) blue, red, white c) red, white, blue d) white, red, blue