An object starts from rest and accelerates uniformly in a straight line in the positive x direction. After 11 seconds, its speed is 70.0 m/s.
-How far does the object travel during the first 11 seconds?
A)35 m
B)77 m
C)390 m
D)590 m
E)770 m

Question

Quizplus · Accepted Answer

We can use the kinematic equation:

v = u + at

Where, 
u = initial velocity (which is zero) 
v = final velocity = 70.0 m/s 
t = time = 11 s 
a = acceleration

Solving for a:

a = (v - u)/t 
a = (70.0 m/s - 0 m/s)/11 s 
a = 6.36 m/s^2

Now, we can use another kinematic equation:

s = ut + (1/2)at^2

Where, 
s = distance traveled 
u = initial velocity (which is zero) 
t = time = 11 s 
a = acceleration = 6.36 m/s^2

Solving for s:

s = (1/2)at^2 
s = (1/2)(6.36 m/s^2)(11 s)^2 
s = 390.11 m

Therefore, the object travels 390.11 meters during the first 11 seconds. 
The closest option is C, 390 m.

An Object Starts from Rest and Accelerates Uniformly in a Straight