physics please help!
posted by Gray on .
A car driving along a straight road increases its velocity from 2.8 m/s to 9.7 m/s in 3 seconds. Calculate its acceleration in m/s^2
A skier in the Giant Slalom will accelerate at a constant 5.0 m/s^2 If she starts from rest, how fast is she going after 5 seconds?
A skier at the top of a run will accelerate at a constant 4.0 ft/s^2 If she starts from rest, how far does she travel in 5 seconds?
Please help me with these 3 questions. I am very confused. Thank you.

<<A car driving along a straight road increases its velocity from 2.8 m/s to 9.7 m/s in 3 seconds. Calculate its acceleration in m/s^2 >>
Divide the increase in velocity (9.72.8 m/s) by the time interval (3 s)
<<A skier in the Giant Slalom will accelerate at a constant 5.0 m/s^2 If she starts from rest, how fast is she going after 5 seconds? >>
Velocity change = (acceleration) x (time)
<<A skier at the top of a run will accelerate at a constant 4.0 ft/s^2 If she starts from rest, how far does she travel in 5 seconds? >>
Distance travelled = (1/2)(acceleration) t^2 
An explorer is caught in a whiteout (in which the snowfall is so thick that the ground cannot be distinguished from the sky) while returning to base camp. He was supposed to travel due north for 5.7 km, but when the snow clears, he discovers that he actually traveled 7.8 km at 52° north of due east. how far must he travel to reach base camp?