# Solve the following :

Question:

A block of mass $2 \mathrm{~kg}$ placed on a long frictionless horizontal table is pulled horizontally by a constant force $F$. It is found to move $10 \mathrm{~m}$ in the first two seconds. Find the magnitude of $F$.

Solution:

$F=m a$

From law of kinematics,

$x-x_{0}=u t+\frac{1}{2} a t^{2}$

$10=\frac{a 2^{2}}{2}$

$(u=0)$

$a=5 m / s^{2}$

$F=m a=2 \times 5=10 \mathrm{~N}$