Question

A body of mass 500 g is thrown vertically upwards with an initial speed of 20 m s-1. What is the magnitude and direction of force due to gravity acting on the body when it is at highest point? [g = 9.8 m s-2].

Answer 1

Given quantities are: $m=500g=0.5kg$and $g=a=9.8m/s^2$
the net force acting on the body at the highest point when thrown upward is given as,
$F=ma$
on substituting the values in the above equation we get,
$$\begin{gathered} F=\left(0.5kg\right)\left(9.8m/s^2\right) \\ F=4.9kg.m/s^2 \\ F=4.9N \end{gathered}$$
Thus, the magnitude of force acting on the body when it reaches its highest point is 4.9 N. The direction of the force acting on the body will be in vertically downward direction.