1543. Back
to High School Physics
Some particle starts moving from rest with
constant acceleration. After time t from the start of the motion, the
particle’s velocity became v. What distance will the particle travel in
time 2t?
Input. Each line is a separate test and contains two integers
– the particle’s velocity v (0 £ v £ 100) and the time t (0 £ t £ 200), at which the particle reached this
velocity.
Output. For each test, print the distance the particle will
move in time 2t on a separate line.
|
Sample
input |
Sample
output |
|
0 0 5 12 |
0 120 |
SOLUTION
mathematics
Algorithm analysis
Let a be the acceleration of the
particle. The distance traveled by a uniformly accelerated particle in time t
is given by at2 / 2.
The velocity of the particle at time t is v = at. In time t1 = 2t, the particle will travel a distance of
s = 
= 
= 2at2
= 2vt (considering that at = v)
Algorithm realization
For each test, read the
input values v and t.
while(scanf("%d %d",
&v,&t) == 2)
The distance that the
particle will travel by time 2t is equal to s = 2vt.
printf("%d\n",2*v*t);