Question 171: Laws of Motion

Question

A force on an object of mass 100 g is $$\left( {10\widehat i + 5\widehat j} \right)$$ N. The position of that object at t = 2 s is $$\left( {a\widehat i + b\widehat j} \right)$$ m after starting from rest. The value of $${a \over b}$$ will be ___________.

Accepted Answer

$$\overrightarrow F  = m\overrightarrow a $$
$$ \Rightarrow \overrightarrow a  = 100\widehat i + 50\widehat j$$
So, $$\overrightarrow S  = {1 \over 2}\overrightarrow a {t^2}$$
$${1 \over 2}\left( {100\widehat i + 50\widehat j} \right){2^2}$$
$$ = 200\widehat i + 100\widehat j$$ m
so a = 200 m and b = 100 m
so $${a \over b} = 2$$

Laws of Motion

A force on an object of mass 100 g is $\left( {10\widehat i + 5\widehat j} \right) N. The position of that object at t = 2 s is \left( {a\widehat i + b\widehat j} \right) m after starting from rest. The value of {a \over b}$ will be ___________.

Choose the correct answer: