A child on a skateboard is traveling at a velocity of 8 m/s down a hill. At the bottom of the hill, he slows down and comes to a stop in 4 seconds. Calculate the sled's deceleration. Depict which equation to use

a=vf-vi/t
t=vf-vi/a
vf=(a•t)+vi

Aspaceship starting from a resting position accelerates at a constant rate of 9.8 meters per second per second. how far will the spaceship travel if its final speed is 1 percent the speed of light (300,000,000 m/s)? a. 3.1 × 106 m b. 2.94 × 108 m c. 7.8 × 1010 m d. 4.6 × 1013 m