A body of mass $4\ kg$ is accelerated upon by a constant force, travels a distance of $5\ m$ in the first second and a distance of $2\ m$ in the third second. The force acting on the body is

Question

Dr. Abubacker · Accepted Answer

(d) The force is constant, $i.e$., the acceleration is constant. The distance is decreasing with time. Therefore it is retardation. 1$^{st}$ second $u.1 - (1/2)a.1 = 5m$ …(i)
3$^{rd}$ second $u.3 - (1/2)a.9 - \left( u.2 - (1/2)a.4 ight) = 3m$
$	herefore u.1 - (1/2)a.5 = 3m$ …(ii)
(i) – (ii) gives $(1/2)a.4 = - 2\  \Rightarrow a = - 1m/s^{2}$
$	herefore$ Constant force $= ma = 4 	imes 1 = 4\ N$
[This is retarding force as $a$ is negative]

Q. A body of mass $4\ kg$ is accelerated upon by a constant force, travels a distance of $5\ m$ in the first second and a distance of $2\ m$ in the third second. The force acting on the body is

Explanation

Reviewed by Dr. Abubacker

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