Question

An object starts from rest and accelerates uniformly. If it moves 2.00m during the first second, then, during the first 5.00 seconds, it will move:________.
a. 7.00 mm .
b. 10.0 mm .
c. 25.0 mm .
d. 50.0 mm .

Answer 1

Answer:

The correct option 50.0 m (the units of the answers are wrong, they should be in meters and not in millimeters).  

Explanation:

From the first second we can find the acceleration of the object:

$X_{f} = X_{0} + V_{0}t + \frac{1}{2}at^{2}$

Where:

$X_{f}$: is the final position = 2.00 m

$X_{0}$: is the initial position = 0

$V_{0}$: is the initial speed = 0 (starts from rest)

t: is the time = 1 s

The acceleration is:

$a = \frac{2X_{f}}{t^{2}} = \frac{4.00 m}{(1 s)^{2}} = 4.00 m/s^{2}$      

Now, we can find the distance after 5 seconds:

$X_{f} = X_{0} + V_{0}t + \frac{1}{2}at^{2} = \frac{1}{2}*4.00 m/s^{2}*(5 s)^{2} = 50.0 m$                  

         

Therefore, the correct answer is 50.0 m. All the options have the units in millimeters and not in meters hence, the units of the options are wrong.

 

I hope it helps you!