Question

The initial velocity of a body moving along a straight line is$7m/s$. It has a uniform acceleration of$4m/s^2$ The distance covered by the body in the$5th$ second of its motion is

• A. $25m$
• B. $35m$
• C. $50m$
• D. $85m$

Answer 1

The correct option is A

$25m$

Step 1: Given data:

The initial velocity of a body moving along a straight line is$\left(u\right)=7m/s$.

The uniform acceleration$\left(a\right)=4m/s^2$

The distance covered by the body $\left(n\right)=5thsecond$

Step 2: Explanation:

The distance covered by the body,

$S_n=u+\left(\frac{a}{2}\right)\left(2n-1\right)$

Now substitute the value in this formula,

$\begin{array}{rcl}{S}_n& =& 7+\left(\frac{4}{2}\right)\left(2\times 5-1\right)\\ S_n& =& 7+2\times 9\\ S_n& =& 25m\end{array}$

Therefore, the distance covered by the body in the 5th second of the motion is $25m$.

Hence, the correct option is A.